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Examples of how to do query, style, dom, ajax, event etc like jQuery with plain javascript.

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You Don't Need jQuery Build Status

Frontend environments evolve rapidly nowadays, modern browsers have already implemented a great deal of DOM/BOM APIs which are good enough. We don't have to learn jQuery from scratch for DOM manipulation or events. In the meantime, thanks to the prevailment of frontend libraries such as React, Angular and Vue, manipulating DOM directly becomes anti-pattern, jQuery has never been less important. This project summarizes most of the jQuery method alternatives in native implementation, with IE 10+ support.

Table of Contents

  1. Translations
  2. Query Selector
  3. CSS & Style
  4. DOM Manipulation
  5. Ajax
  6. Events
  7. Utilities
  8. Promises
  9. Animation
  10. Alternatives
  11. Browser Support

Translations

Query Selector

In place of common selectors like class, id or attribute we can use document.querySelector or document.querySelectorAll for substitution. The differences lie in:

  • document.querySelector returns the first matched element
  • document.querySelectorAll returns all matched elements as NodeList. It can be converted to Array using Array.prototype.slice.call(document.querySelectorAll(selector));
  • If there are no elements matched, jQuery and document.querySelectorAll will return [], whereas document.querySelector will return null.

Notice: document.querySelector and document.querySelectorAll are quite SLOW, try to use document.getElementById, document.getElementsByClassName or document.getElementsByTagName if you want to get a performance bonus.

  • 1.0 Query by selector

    // jQuery
    $('selector');
    
    // Native
    document.querySelectorAll('selector');
  • 1.1 Query by class

    // jQuery
    $('.class');
    
    // Native
    document.querySelectorAll('.class');
    
    // or
    document.getElementsByClassName('class');
  • 1.2 Query by id

    // jQuery
    $('#id');
    
    // Native
    document.querySelector('#id');
    
    // or
    document.getElementById('id');
  • 1.3 Query by attribute

    // jQuery
    $('a[target=_blank]');
    
    // Native
    document.querySelectorAll('a[target=_blank]');
  • 1.4 Query in descendents

    // jQuery
    $el.find('li');
    
    // Native
    el.querySelectorAll('li');
  • 1.5 Sibling/Previous/Next Elements

    • Sibling elements

      // jQuery
      $el.siblings();
      
      // Native
      Array.prototype.filter.call(el.parentNode.children, (child) =>
        child !== el
      );
    • Previous elements

      // jQuery
      $el.prev();
      
      // Native
      el.previousElementSibling;
    • Next elements

      // jQuery
      $el.next();
      
      // Native
      el.nextElementSibling;
  • 1.6 Closest

    Return the first matched element by provided selector, traversing from current element to document.

    // jQuery
    $el.closest(selector);
    
    // Native - Only latest, NO IE
    el.closest(selector);
    
    // Native - IE10+
    function closest(el, selector) {
      const matchesSelector = el.matches || el.webkitMatchesSelector || el.mozMatchesSelector || el.msMatchesSelector;
    
      while (el) {
        if (matchesSelector.call(el, selector)) {
          return el;
        } else {
          el = el.parentElement;
        }
      }
      return null;
    }
  • 1.7 Parents Until

    Get the ancestors of each element in the current set of matched elements, up to but not including the element matched by the selector, DOM node, or jQuery object.

    // jQuery
    $el.parentsUntil(selector, filter);
    
    // Native
    function parentsUntil(el, selector, filter) {
      const result = [];
      const matchesSelector = el.matches || el.webkitMatchesSelector || el.mozMatchesSelector || el.msMatchesSelector;
    
      // match start from parent
      el = el.parentElement;
      while (el && !matchesSelector.call(el, selector)) {
        if (!filter) {
          result.push(el);
        } else {
          if (matchesSelector.call(el, filter)) {
            result.push(el);
          }
        }
        el = el.parentElement;
      }
      return result;
    }
  • 1.8 Form

    • Input/Textarea

      // jQuery
      $('#my-input').val();
      
      // Native
      document.querySelector('#my-input').value;
    • Get index of e.currentTarget between .radio

      // jQuery
      $('.radio').index(e.currentTarget);
      
      // Native
      Array.prototype.indexOf.call(document.querySelectorAll('.radio'), e.currentTarget);
  • 1.9 Iframe Contents

    $('iframe').contents() returns contentDocument for this specific iframe

    • Iframe contents

      // jQuery
      $iframe.contents();
      
      // Native
      iframe.contentDocument;
    • Iframe Query

      // jQuery
      $iframe.contents().find('.css');
      
      // Native
      iframe.contentDocument.querySelectorAll('.css');
  • 1.10 Get body

    // jQuery
    $('body');
    
    // Native
    document.body;
  • 1.11 Attribute getter and setter

    • Get an attribute

      // jQuery
      $el.attr('foo');
      
      // Native
      el.getAttribute('foo');
    • Set an attribute

      // jQuery, note that this works in memory without change the DOM
      $el.attr('foo', 'bar');
      
      // Native
      el.setAttribute('foo', 'bar');
    • Get a data- attribute

      // jQuery
      $el.data('foo');
      
      // Native (use `getAttribute`)
      el.getAttribute('data-foo');
      
      // Native (use `dataset` if only need to support IE 11+)
      el.dataset['foo'];

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CSS & Style

  • 2.1 CSS

    • Get style

      // jQuery
      $el.css('color');
      
      // Native
      // NOTE: Known bug, will return 'auto' if style value is 'auto'
      const win = el.ownerDocument.defaultView;
      
      // null means not to return pseudo styles
      win.getComputedStyle(el, null).color;
    • Set style

      // jQuery
      $el.css({ color: '#f01' });
      
      // Native
      el.style.color = '#f01';
    • Get/Set Styles

      Note that if you want to set multiple styles once, you could refer to setStyles method in oui-dom-utils package.

    • Add class

      // jQuery
      $el.addClass(className);
      
      // Native
      el.classList.add(className);
    • Remove class

      // jQuery
      $el.removeClass(className);
      
      // Native
      el.classList.remove(className);
    • has class

      // jQuery
      $el.hasClass(className);
      
      // Native
      el.classList.contains(className);
    • Toggle class

      // jQuery
      $el.toggleClass(className);
      
      // Native
      el.classList.toggle(className);
  • 2.2 Width & Height

    Width and Height are theoretically identical, take Height as example:

    • Window height

      // window height
      $(window).height();
      
      // with scrollbar
      window.document.documentElement.clientHeight;
      
      // without scrollbar, behaves like jQuery
      window.innerHeight;
    • Document height

      // jQuery
      $(document).height();
      
      // Native
      const body = document.body;
      const html = document.documentElement;
      const height = Math.max(
        body.offsetHeight,
        body.scrollHeight,
        html.clientHeight,
        html.offsetHeight,
        html.scrollHeight
      );
    • Element height

      // jQuery
      $el.height();
      
      // Native
      function getHeight(el) {
        const styles = window.getComputedStyle(el);
        const height = el.offsetHeight;
        const borderTopWidth = parseFloat(styles.borderTopWidth);
        const borderBottomWidth = parseFloat(styles.borderBottomWidth);
        const paddingTop = parseFloat(styles.paddingTop);
        const paddingBottom = parseFloat(styles.paddingBottom);
        return height - borderBottomWidth - borderTopWidth - paddingTop - paddingBottom;
      }
      
      // accurate to integer(when `border-box`, it's `height - border`; when `content-box`, it's `height + padding`)
      el.clientHeight;
      
      // accurate to decimal(when `border-box`, it's `height`; when `content-box`, it's `height + padding + border`)
      el.getBoundingClientRect().height;
  • 2.3 Position & Offset

    • Position

      Get the current coordinates of the element relative to the offset parent.

      // jQuery
      $el.position();
      
      // Native
      { left: el.offsetLeft, top: el.offsetTop }
    • Offset

      Get the current coordinates of the element relative to the document.

      // jQuery
      $el.offset();
      
      // Native
      function getOffset (el) {
        const box = el.getBoundingClientRect();
      
        return {
          top: box.top + window.pageYOffset - document.documentElement.clientTop,
          left: box.left + window.pageXOffset - document.documentElement.clientLeft
        };
      }
  • 2.4 Scroll Top

    Get the current vertical position of the scroll bar for the element.

    // jQuery
    $(window).scrollTop();
    
    // Native
    (document.documentElement && document.documentElement.scrollTop) || document.body.scrollTop;

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DOM Manipulation

  • 3.1 Remove

    Remove the element from the DOM.

    // jQuery
    $el.remove();
    
    // Native
    el.parentNode.removeChild(el);
  • 3.2 Text

    • Get text

      Get the combined text contents of the element including their descendants,

      // jQuery
      $el.text();
      
      // Native
      el.textContent;
    • Set text

      Set the content of the element to the specified text.

      // jQuery
      $el.text(string);
      
      // Native
      el.textContent = string;
  • 3.3 HTML

    • Get HTML

      // jQuery
      $el.html();
      
      // Native
      el.innerHTML;
    • Set HTML

      // jQuery
      $el.html(htmlString);
      
      // Native
      el.innerHTML = htmlString;
  • 3.4 Append

    Append child element after the last child of parent element

    // jQuery
    $el.append('<div id="container">Hello World</div>');
    
    // Native (HTML string)
    el.insertAdjacentHTML('beforeend', '<div id="container">Hello World</div>');
    
    // Native (Element)
    el.appendChild(newEl);
  • 3.5 Prepend

    // jQuery
    $el.prepend('<div id="container">Hello World</div>');
    
    // Native (HTML string)
    el.insertAdjacentHTML('afterbegin', '<div id="container">Hello World</div>');
    
    // Native (Element)
    el.insertBefore(newEl, el.firstChild);
  • 3.6 insertBefore

    Insert a new node before the selected elements

    // jQuery
    $newEl.insertBefore(selector);
    
    // Native (HTML string)
    el.insertAdjacentHTML('beforebegin ', '<div id="container">Hello World</div>');
    
    // Native (Element)
    const el = document.querySelector(selector);
    if (el.parentNode) {
      el.parentNode.insertBefore(newEl, el);
    }
  • 3.7 insertAfter

    Insert a new node after the selected elements

    // jQuery
    $newEl.insertAfter(selector);
    
    // Native (HTML string)
    el.insertAdjacentHTML('afterend', '<div id="container">Hello World</div>');
    
    // Native (Element)
    const el = document.querySelector(selector);
    if (el.parentNode) {
      el.parentNode.insertBefore(newEl, el.nextSibling);
    }
  • 3.8 is

    Return true if it matches the query selector

    // jQuery - Notice `is` also work with `function` or `elements` which is not concerned here
    $el.is(selector);
    
    // Native
    el.matches(selector);
  • 3.9 clone

    Create a deep copy of that element

    // jQuery
    $el.clone();
    
    // Native
    el.cloneNode();
    
    // For Deep clone , set param as `true`
  • 3.10 empty

    Remove all child nodes

    // jQuery
    $el.empty();
    
    // Native
    el.innerHTML = '';
  • 3.11 wrap

    Wrap an HTML structure around each element

    // jQuery
    $('.inner').wrap('<div class="wrapper"></div>');
    
    // Native
    Array.prototype.forEach.call(document.querySelectorAll('.inner'), (el) => {
      const wrapper = document.createElement('div');
      wrapper.className = 'wrapper';
      el.parentNode.insertBefore(wrapper, el);
      el.parentNode.removeChild(el);
      wrapper.appendChild(el);
    });
  • 3.12 unwrap

    Remove the parents of the set of matched elements from the DOM

    // jQuery
    $('.inner').unwrap();
    
    // Native
    Array.prototype.forEach.call(document.querySelectorAll('.inner'), (el) => {
      Array.prototype.forEach.call(el.childNodes, (child) => {
        el.parentNode.insertBefore(child, el);
      });
      el.parentNode.removeChild(el);
    });
  • 3.13 replaceWith

    Replace each element in the set of matched elements with the provided new content

    // jQuery
    $('.inner').replaceWith('<div class="outer"></div>');
    
    // Native
    Array.prototype.forEach.call(document.querySelectorAll('.inner'), (el) => {
      const outer = document.createElement('div');
      outer.className = 'outer';
      el.parentNode.insertBefore(outer, el);
      el.parentNode.removeChild(el);
    });

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Ajax

Fetch API is the new standard to replace XMLHttpRequest to do ajax. It works on Chrome and Firefox, you can use polyfills to make it work on legacy browsers.

Try github/fetch on IE9+ or fetch-ie8 on IE8+, fetch-jsonp to make JSONP requests.

  • 4.1 Load data from the server and place the returned HTML into the matched element.

    // jQuery
    $(selector).load(url, completeCallback)
    
    // Native
    fetch(url).then(data => data.text()).then(data => {
      document.querySelector(selector).innerHTML = data
    }).then(completeCallback)

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Events

For a complete replacement with namespace and delegation, refer to https://github.com/oneuijs/oui-dom-events

  • 5.0 Document ready by DOMContentLoaded

    // jQuery
    $(document).ready(eventHandler);
    
    // Native
    // Check if the DOMContentLoaded has already been completed
    if (document.readyState === 'complete' || document.readyState !== 'loading') {
      eventHandler();
    } else {
      document.addEventListener('DOMContentLoaded', eventHandler);
    }
  • 5.1 Bind an event with on

    // jQuery
    $el.on(eventName, eventHandler);
    
    // Native
    el.addEventListener(eventName, eventHandler);
  • 5.2 Unbind an event with off

    // jQuery
    $el.off(eventName, eventHandler);
    
    // Native
    el.removeEventListener(eventName, eventHandler);
  • 5.3 Trigger

    // jQuery
    $(el).trigger('custom-event', {key1: 'data'});
    
    // Native
    if (window.CustomEvent) {
      const event = new CustomEvent('custom-event', {detail: {key1: 'data'}});
    } else {
      const event = document.createEvent('CustomEvent');
      event.initCustomEvent('custom-event', true, true, {key1: 'data'});
    }
    
    el.dispatchEvent(event);

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Utilities

Most of utilities are found by native API. Others advanced functions could be choosed better utilities library focus on consistency and performance. Recommend lodash to replace.

  • 6.1 Basic utilities

    • isArray

    Determine whether the argument is an array.

    // jQuery
    $.isArray(array);
    
    // Native
    Array.isArray(array);
    • isWindow

    Determine whether the argument is a window.

    // jQuery
    $.isWindow(obj);
    
    // Native
    function isWindow(obj) {
      return obj !== null && obj !== undefined && obj === obj.window;
    }
    • inArray

    Search for a specified value within an array and return its index (or -1 if not found).

    // jQuery
    $.inArray(item, array);
    
    // Native
    array.indexOf(item) > -1;
    
    // ES6-way
    array.includes(item);
    • isNumeric

    Determine if the argument passed is numerical. Use typeof to decide the type or the type example for better accuracy.

    // jQuery
    $.isNumeric(item);
    
    // Native
    function isNumeric(value) {
      var type = typeof value;
    
      return (type === 'number' || type === 'string') && !Number.isNaN(value - Number.parseFloat(value));
    }
    • isFunction

    Determine if the argument passed is a JavaScript function object.

    // jQuery
    $.isFunction(item);
    
    // Native
    function isFunction(item) {
      if (typeof item === 'function') {
        return true;
      }
      var type = Object.prototype.toString(item);
      return type === '[object Function]' || type === '[object GeneratorFunction]';
    }
    • isEmptyObject

    Check to see if an object is empty (contains no enumerable properties).

    // jQuery
    $.isEmptyObject(obj);
    
    // Native
    function isEmptyObject(obj) {
      return Object.keys(obj).length === 0;
    }
    • isPlainObject

    Check to see if an object is a plain object (created using “{}” or “new Object”).

    // jQuery
    $.isPlainObject(obj);
    
    // Native
    function isPlainObject(obj) {
      if (typeof (obj) !== 'object' || obj.nodeType || obj !== null && obj !== undefined && obj === obj.window) {
        return false;
      }
    
      if (obj.constructor &&
          !Object.prototype.hasOwnProperty.call(obj.constructor.prototype, 'isPrototypeOf')) {
        return false;
      }
    
      return true;
    }
    • extend

    Merge the contents of two or more objects together into the first object. object.assign is ES6 API, and you could use polyfill also.

    // jQuery
    $.extend({}, defaultOpts, opts);
    
    // Native
    Object.assign({}, defaultOpts, opts);
    • trim

    Remove the white-space from the beginning and end of a string.

    // jQuery
    $.trim(string);
    
    // Native
    string.trim();
    • map

    Translate all items in an array or object to new array of items.

    // jQuery
    $.map(array, (value, index) => {
    });
    
    // Native
    array.map((value, index) => {
    });
    • each

    A generic iterator function, which can be used to seamlessly iterate over both objects and arrays.

    // jQuery
    $.each(array, (index, value) => {
    });
    
    // Native
    array.forEach((value, index) => {
    });
    • grep

    Finds the elements of an array which satisfy a filter function.

    // jQuery
    $.grep(array, (value, index) => {
    });
    
    // Native
    array.filter((value, index) => {
    });
    • type

    Determine the internal JavaScript [Class] of an object.

    // jQuery
    $.type(obj);
    
    // Native
    function type(item) {
      const reTypeOf = /(?:^\[object\s(.*?)\]$)/;
      return Object.prototype.toString.call(item)
        .replace(reTypeOf, '$1')
        .toLowerCase();
    }
    • merge

    Merge the contents of two arrays together into the first array.

    // jQuery
    $.merge(array1, array2);
    
    // Native
    // But concat function doesn't remove duplicate items.
    function merge(...args) {
      return [].concat(...args)
    }
    • now

    Return a number representing the current time.

    // jQuery
    $.now();
    
    // Native
    Date.now();
    • proxy

    Takes a function and returns a new one that will always have a particular context.

    // jQuery
    $.proxy(fn, context);
    
    // Native
    fn.bind(context);
    • makeArray

    Convert an array-like object into a true JavaScript array.

    // jQuery
    $.makeArray(arrayLike);
    
    // Native
    Array.prototype.slice.call(arrayLike);
    
    // ES6-way
    Array.from(arrayLike);
  • 6.2 Contains

    Check to see if a DOM element is a descendant of another DOM element.

    // jQuery
    $.contains(el, child);
    
    // Native
    el !== child && el.contains(child);
  • 6.3 Globaleval

    Execute some JavaScript code globally.

    // jQuery
    $.globaleval(code);
    
    // Native
    function Globaleval(code) {
      const script = document.createElement('script');
      script.text = code;
    
      document.head.appendChild(script).parentNode.removeChild(script);
    }
    
    // Use eval, but context of eval is current, context of $.Globaleval is global.
    eval(code);
  • 6.4 parse

    • parseHTML

    Parses a string into an array of DOM nodes.

    // jQuery
    $.parseHTML(htmlString);
    
    // Native
    function parseHTML(string) {
      const context = document.implementation.createHTMLDocument();
    
      // Set the base href for the created document so any parsed elements with URLs
      // are based on the document's URL
      const base = context.createElement('base');
      base.href = document.location.href;
      context.head.appendChild(base);
    
      context.body.innerHTML = string;
      return context.body.children;
    }
    • parseJSON

    Takes a well-formed JSON string and returns the resulting JavaScript value.

    // jQuery
    $.parseJSON(str);
    
    // Native
    JSON.parse(str);

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Promises

A promise represents the eventual result of an asynchronous operation. jQuery has its own way to handle promises. Native JavaScript implements a thin and minimal API to handle promises according to the Promises/A+ specification.

  • 7.1 done, fail, always

    done is called when promise is resolved, fail is called when promise is rejected, always is called when promise is either resolved or rejected.

    // jQuery
    $promise.done(doneCallback).fail(failCallback).always(alwaysCallback)
    
    // Native
    promise.then(doneCallback, failCallback).then(alwaysCallback, alwaysCallback)
  • 7.2 when

    when is used to handle multiple promises. It will resolve when all promises are resolved, and reject if either one is rejected.

    // jQuery
    $.when($promise1, $promise2).done((promise1Result, promise2Result) => {
    });
    
    // Native
    Promise.all([$promise1, $promise2]).then([promise1Result, promise2Result] => {});
  • 7.3 Deferred

    Deferred is a way to create promises.

    // jQuery
    function asyncFunc() {
      const defer = new $.Deferred();
      setTimeout(() => {
        if(true) {
          defer.resolve('some_value_computed_asynchronously');
        } else {
          defer.reject('failed');
        }
      }, 1000);
    
      return defer.promise();
    }
    
    // Native
    function asyncFunc() {
      return new Promise((resolve, reject) => {
        setTimeout(() => {
          if (true) {
            resolve('some_value_computed_asynchronously');
          } else {
            reject('failed');
          }
        }, 1000);
      });
    }
    
    // Deferred way
    function defer() {
      const deferred = {};
      const promise = new Promise((resolve, reject) => {
        deferred.resolve = resolve;
        deferred.reject = reject;
      });
    
      deferred.promise = () => {
        return promise;
      };
    
      return deferred;
    }
    
    function asyncFunc() {
      const defer = defer();
      setTimeout(() => {
        if(true) {
          defer.resolve('some_value_computed_asynchronously');
        } else {
          defer.reject('failed');
        }
      }, 1000);
    
      return defer.promise();
    }

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Animation

  • 8.1 Show & Hide

    // jQuery
    $el.show();
    $el.hide();
    
    // Native
    // More detail about show method, please refer to https://github.com/oneuijs/oui-dom-utils/blob/master/src/index.js#L363
    el.style.display = ''|'inline'|'inline-block'|'inline-table'|'block';
    el.style.display = 'none';
  • 8.2 Toggle

    Display or hide the element.

    // jQuery
    $el.toggle();
    
    // Native
    if (el.ownerDocument.defaultView.getComputedStyle(el, null).display === 'none') {
      el.style.display = ''|'inline'|'inline-block'|'inline-table'|'block';
    } else {
      el.style.display = 'none';
    }
  • 8.3 FadeIn & FadeOut

    // jQuery
    $el.fadeIn(3000);
    $el.fadeOut(3000);
    
    // Native
    el.style.transition = 'opacity 3s';
    // fadeIn
    el.style.opacity = '1';
    // fadeOut
    el.style.opacity = '0';
  • 8.4 FadeTo

    Adjust the opacity of the element.

    // jQuery
    $el.fadeTo('slow',0.15);
    // Native
    el.style.transition = 'opacity 3s'; // assume 'slow' equals 3 seconds
    el.style.opacity = '0.15';
  • 8.5 FadeToggle

    Display or hide the element by animating their opacity.

    // jQuery
    $el.fadeToggle();
    
    // Native
    el.style.transition = 'opacity 3s';
    const { opacity } = el.ownerDocument.defaultView.getComputedStyle(el, null);
    if (opacity === '1') {
      el.style.opacity = '0';
    } else {
      el.style.opacity = '1';
    }
  • 8.6 SlideUp & SlideDown

    // jQuery
    $el.slideUp();
    $el.slideDown();
    
    // Native
    const originHeight = '100px';
    el.style.transition = 'height 3s';
    // slideUp
    el.style.height = '0px';
    // slideDown
    el.style.height = originHeight;
  • 8.7 SlideToggle

    Display or hide the element with a sliding motion.

    // jQuery
    $el.slideToggle();
    
    // Native
    const originHeight = '100px';
    el.style.transition = 'height 3s';
    const { height } = el.ownerDocument.defaultView.getComputedStyle(el, null);
    if (parseInt(height, 10) === 0) {
      el.style.height = originHeight;
    }
    else {
     el.style.height = '0px';
    }
  • 8.8 Animate

    Perform a custom animation of a set of CSS properties.

    // jQuery
    $el.animate({ params }, speed);
    
    // Native
    el.style.transition = 'all ' + speed;
    Object.keys(params).forEach((key) =>
      el.style[key] = params[key];
    )

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Examples of how to do query, style, dom, ajax, event etc like jQuery with plain javascript.

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