Define variable before javascript load

Question

I noticed that you can't import a javascript file and define a variable in the same <script>.

This is my problem:

<script type="text/javascript" src="js.js">
var id = "587587";
</script>

Is there a way to load the javascript after the variable without using another <script> tag?

You could first define the variable and then do something like document.write('<script src="js.js"><\/script>') in the javascript. But then again, why not insert the script tag manually? — agrm
– agrm, Commented Jul 5, 2014 at 16:01
Because I'll be implementing it into a system where users will copy the code into their own websites, so it needs to be clean. — George
– George, Commented Jul 5, 2014 at 16:01
Writing a script tag programmatically is typically what most analytics scripts do. But some also use a second script tag. IMO it's not any worse, the user needs to copy and paste some meaningless blob anyway, he'll hardly care what exactly that blob contains. — deceze
– deceze ♦, Commented Jul 5, 2014 at 16:04
@George - perhaps you could ask the (maybe a different) question in a way that illustrates the problem you're trying to solve instead of a work around for not being able to use the script tag like you want. You might get better answers. — tvanfosson
– tvanfosson, Commented Jul 5, 2014 at 16:04

Alexander O'Mara · Accepted Answer · 2014-07-05 16:02:25Z

1

If a script tag has a src attribute, anything between the script tags is ignored. The only way you could do something like this is by dynamically adding a new script tag with an ugly hack like this.

<script type="text/javascript">
var id = "587587";
document.write('<script type="text/javascript" src="js.js"><\/script>');
</script>

Using another script tag before the one with the id would certainly be the preferable and shorter solution.

answered Jul 5, 2014 at 16:02

Alexander O'Mara

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deceze · Accepted Answer · 2014-07-05 16:02:28Z

1

src

This attribute specifies the URI of an external script; this can be used as an alternative to embedding a script directly within a document. script elements with an src attribute specified should not have a script embedded within its tags.

http://developer.mozilla.org/en-US/docs/Web/HTML/Element/script.html

So, you either have an external script, or you have something inside the <script> tag. You shouldn't have both at once; I'm not sure whether this actually does anything or not.

Use a second script tag.

answered Jul 5, 2014 at 16:02

deceze♦

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2 Comments

dandavis Over a year ago

the contents of a .scr-having tag don't "do anything", but they are present in the dom by any other script.

deceze Over a year ago

@dandavis "...whether having source code within the tags when you already have a src attribute does anything..."

MTGradwell · Accepted Answer · 2014-07-05 16:30:32Z

0

A script element must either contain script code between the script start and end tags, or reference external script code via the src= attribute. It cannot do both. However, your external code can reference the details of your HTML via the DOM (Document Object Model). So you can treat any HTML element (e.g. a text input field) as a parameter to be passed to your external javascript, where it can be read by e.g. var param = document.getElementById('param').innerHTML;

answered Jul 5, 2014 at 16:30

MTGradwell

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