Call javascript var inside other script

Question

I have this code:

<script type="text/javascript">
var rndn = Math.round(Math.random()*1000000);
</script>
<script type="text/javascript" src="http://myexample.com/call=cid&rnd=7676786"></script>

I need to recall the "rndn" var to replace the number 7676786 in the second script.

How do I do that?

• Alexander Elgin: You can find answer here: stackoverflow.com/questions/950087/…

Answer 1

I think this is the best way to do it:

<script type="text/javascript">
var rndn = Math.round(Math.random()*1000000);
var myScript = document.createElement('script');
myScript.setAttribute('src','http://myexample.com/call=cid&rnd='+rnd);
document.head.appendChild(myScript);
</script>

• Luis González: I like it, but why not simply add a new 'src' attribute to an existing script node? Check my answer to understand what I am saying
• NewToJS: @Pradeep I would go for this method if the script tag only needed to be created once but if the OP want's to change the url parameter for whatever reason I would give the script tag an id, check if the element exists, if so update it, if not then create it.
• Pradeep: @NewToJS this is just a demo, OP can customize it to his/her requirement.

Answer 2

This should work:

<script type="text/javascript" src="javascript:'http://myexample.com/call=cid&rnd='+rndn"></script>

Answer 3

Simply:

<script id="other_script" type="text/javascript">
</script>
<script type="text/javascript">
var rndn = Math.round(Math.random()*1000000);
document.getElementById("other_script").setAttribute("src","http://myexample.com/call=cid&rnd="+rndn);
</script>

• Andreas: document.getElementById("other_script") will be null, and why the jQuery part?
• NewToJS: This should be placed in - window.onload=function(){//Here} otherwise the javascript will run before the browser knows other_script exists or it could be placed in another function and have window.onload=MyFunc; to call it when the DOM is ready.
• Andreas: @NewToJS Not necessarily. Just swap the script blocks.
• NewToJS: @Andreas You can just swap the script tags but the point is the original answer wouldn't work. I was offering a way of fixing the answer.
• NewToJS: @Andreas So why swap the order of the script tags? Now you're contradicting yourself. The original answer luigonsec posted would return Uncaught TypeError: Cannot read property 'setAttribute' of null in the console hence me offering a solution to fix the answer. The browser has to read the elements before you can attempt to change them.

Answer 4

I found out that the best way to do this is:

<script type="text/javascript">
var rndn = Math.round(Math.random()*1000000);
document.write('<scri'+'pt language=\"Javascript\" src=\"http://myexample.com/call=cid&rnd='+rndn+'"></scri'+'pt>');
</script>

• Andreas: @NewToJS There's absolutely no problem with document.write() as long as it is used before the page has finished loading.