I'm trying to do something fairly simple, but for the reason of me probably not being good enough to search documentation, I can't get this to work.
I have a functioning inline JS that looks like this:
<A title=Wolfram IP Calc href=javascript:txt=prompt('Enter%20IP%20address,%20e.g.%2010.20.30.40/29','1.2.3.4/5');%20if(txt)%20window.open('http://www.wolframalpha.com/input/?i='+txt);void(O);>Compute!</A>
For various reasons, I'm trying to seperate the JS, and this is where I hit a snag.
I've created the following test page that gives me the error Uncaught TypeError: Cannot call method 'addEventListener' of null:
<HTML> <HEAD profile=http://www.w3.org/2005/10/profile> <script type=text/javascript>
var compute = document.getElementById('compute');
compute.addEventListener('click', computeThatThing, false);
function computeThatThing() {
txt=prompt('Enter%20IP%20address,%20e.g.%2010.20.30.40/29','1.2.3.4/5');
if(txt) {
window.open('http://www.wolframalpha.com/input/?i='+txt);
}
}
</script></HEAD>
<BODY>
<A title=Wolfram IP Calc id=compute href=javascript:void(O);>Test</A>
</BODY>
</HTML>
The only thing I've been able to find that points to a problem like that is that addEventListener can't work with <A> but should handle <IMG> (which suits me fine as I'm going to pour this on some images), so I tried adding the following to no avail:
<img id=compute src=http://products.wolframalpha.com/images/products/products-wa.png />
Thanks in advance for pointing out what I'm doing wrong. It is probably glaringly obvious, but I have close to zero experience with JS and I have gone mostly by cargo culting when I've needed it until now.
