Home/ Questions/Q 7047855
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-28T02:49:18+00:00

I can’t figure out what is wrong with my code here. I am trying

  • 0

I can’t figure out what is wrong with my code here. I am trying to load jQuery dynamically if it is not present on the page. 

<head>
  <script>
     (function() {
         if (typeof jQuery != 'undefined') {
         /* jQuery is already loaded... verify minimum version number of 1.4.2 and reload newer if needed */
         if (/1\.(0|1|2|3|4)\.(0|1)/.test(jQuery.fn.jquery) || /^1.1/.test(jQuery.fn.jquery) || /^1.2/.test(jQuery.fn.jquery)|| /^1.3/.test(jQuery.fn.jquery)) {
         loadJQ();
         }
      } else {
           loadJQ();
        }

    function loadJQ() {
    /* adds a link to jQuery to the head, instead of inline, so it validates */ 
    var headElement = document.getElementsByTagName("head")[0];
    linkElement=document.createElement("script");
    linkElement.src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js";
    linkElement.type="text/javascript";
    headElement.appendChild(linkElement);
   //alert(headElement);
   }

   })();

  </script>
</head>

This is my body.

 <body>
   <button>Click me</button>
   <script type="text/javascript">
     $(document).ready(function(){
   alert("hello");
     $("button").click(function(){
     $(this).hide();
    });
   });
   </script>
 </body>

When I put this in a html page I get an error saying that “$ is not defined”. Anyone has any idea why?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    With help of one my friend, found what is the problem with above code.

    When the document.ready runs, jquery is not on the page (there are two onReady elements running)… and since the addToHead version is non-blocking, the rest of the javascript executes in parallel and fails.

    I added this just after the body tag starts and it works fine: 

    <script type="text/javascript">
   if (typeof jQuery == 'undefined') {
     document.write('<scr'+'ipt type="text/javascript" src="http://ajax.googleapis.com /ajax/libs/jquery/1.7.1/jquery.min.js">'+'</scr'+'ipt>');
  }
</script>
    • 0