Why can't I execute JavaScript function inside the <script> tag that defines the .js source?

Question

I am defining the source of a .js file and attempting to call a function from that file in the same tag, as follows:

<script type="text/javascript" src="jsFunctionTest.js">
    testMethodCall();
</script>

The .js file just contains:

function testMethodCall(){
    window.alert("Hello there");
}

This doesn't work, I don't see the alert.

However, if I change the tag to two tags, as below, then it works:

<script type="text/javascript" src="jsFunctionTest.js"></script>
<script type="text/javascript">
    testMethodCall();
</script>

This seems pretty messy. Is there any reason the first one doesn't work?

Answer 1

script elements can have a src attribute or content, but not both. If they have both, the content is ignored (the content is considered "script documentation," not code).

Answer 2

You cannot register an external file and use the content in it, both at a time inside <script> tags. Only either one is allowed.