Is there a way to execute jQuery similar to window.eval() in JavaScript?

This is because jQuery didn't load yet, you could attach a onload or check onreadystatechanged on the iframe to figure out when it has loaded.

The reason could be your iframe does not load jquery library. Try:

var js = ""; // JavaScript or jQuery code here var preview = document.createElement('script'); preview.src = "http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js" ; frames[0].window.document.body.appendChild(preview); frames[0].window.eval(js); 

• document.createElement('script'); instead of document.createElement('iframe_id');
• Execute this line frames[0].window.document.body.appendChild(preview); to load jquery for your iframe.

You have to make sure jQuery script is loaded before you try to eval code that uses jQuery syntax. Take a look at this thread https://stackoverflow.com/a/6725358/937367.

function scriptTag(src, callback) { var s = document.createElement('script'); s.type = 'text/' + (src.type || 'javascript'); s.src = src.src || src; s.async = false; s.onreadystatechange = s.onload = function() { var state = s.readyState; if (!callback.done && (!state || /loaded|complete/.test(state))) { callback.done = true; callback(); } }; // use body if available. more safe in IE (document.body || head).appendChild(s); } 

Eval your code in callback function like below and all should be fine.

var js = ""; // JavaScript or jQuery code here scriptTag("http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js", function(){ frames[0].window.eval(js); }); 

I tested it here http://jsfiddle.net/SFUbg/2/. I don't know why in that scriptTag function doc was used instead of document, as this is no equivalent, so I changed it.

jQuery is not a separate language. At least one reason your code will not work is that createElement takes a tag name, which 'iframe_id' is not.

Also, you are setting the src of the iframe directly to jQuery. You should be setting it to an HTML page, or about:blank, then somehow loading jQuery. The easiest way to load it is simply to set the iframe URL to a HTML page with an explicit loading jQuery.

EDIT: If the iframe already exists and is loaded, and you just want to add jQuery to it, Jan.J's answer should help.

Here's code we're using quite successfully in a project that uses multiple iframes, adapted to your what you're seemingly doing:

function setContent(source) { var iframe = document.createElement("iframe"); iframe.style.opacity = 0.0; document.body.appendChild(iframe); // set new content doc = iframe.contentDocument; doc.open(); doc.write(sourceCode); doc.close(); // kill off old iframe document.body.removeChild(document.querySelector("iframe")); iframe.style.opacity = 1.0; // inject the script you needed var scriptElement = doc.createElement("script"); scriptElement.src = "..."; doc.querySelector("head").appendChild(scriptElement); } 

And have a http://jsbin.com/iFoZAdU/8/edit for the working code.

Now never post five identical questions again please.