Introduction 
 
I had a requirement to generate the GUID type id using JavaScript. I started worked on that, in the mean while I came across some sites and they already have given some snippets to generate the GUID.
 
Here, I will give those compilations of those snippets.
 
Generate random unique id / GUID using Math.Random 
 
Example 1: 
     -   
- function CreateGuid() {  
-    function _p8(s) {  
-       var p = (Math.random().toString(16)+"000000000").substr(2,8);  
-       return s ? "-" + p.substr(0,4) + "-" + p.substr(4,4) : p ;  
-    }  
-    return _p8() + _p8(true) + _p8(true) + _p8();  
- }  
-   
- var guid = createGuid();  
 
 
Example 2:
     -   
-   
- function createGuid(){  
-    function S4() {  
-       return (((1+Math.random())*0x10000)|0).toString(16).substring(1);  
-    }  
-    return (S4() + S4() + "-" + S4() + "-4" + S4().substr(0,3) + "-" + S4() + "-" + S4() + S4() + S4()).toLowerCase();  
- }  
-   
- var guid = createGuid();   
 
 
Example 3: 
     -   
-   
- function createGuid() {  
-    function s4() {  
-       return Math.floor((1 + Math.random()) * 0x10000).toString(16).substring(1);  
-    }  
-    return s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4();  
- }  
-   
- var guid = createguid();  
 
 
Generate GUID using the Regular Expression
 
Example 4: 
     -   
-   
- function createGuid()  
- {  
-    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {  
-       var r = Math.random()*16|0, v = c === 'x' ? r : (r&0x3|0x8);  
-       return v.toString(16);  
-    });  
- }  
-   
- var guid = createGuid();