added session storage

Author: ummeabiha

SessionStorage.js

@@ -0,0 +1,28 @@
+/*
+properties and methods are similar to local storage.
+Session storage exists in current browser tab only.
+if we change the tabs, the session storage will be cleared. 
+
+The data survives the page refresh, but not closing/opening the tab.
+
+STORAGE EVENT
+When the data is updated in local or session storage, storage event must be triggered with the following properties:
+1- key
+2- old value
+3- new value
+4- url
+5- storageArea
+*/
+
+// sessionStorage.getItem("name")
+// sessionStorage.clear()
+// sessionStorage.removeItem("name")
+// sessionStorage.setItem("name", "harry")
+// sessionStorage.removeItem("name")
+
+
+window.onstorage = (e) => {
+        alert("changed")
+        console.log(e)
+}
+