I'm trying to follow the guide here http://www.appelsiini.net/projects/chained
for chaining multiple select boxes, but I'm very new to javascript and everything front end in general.
I thought I had copied his example by creating the following HTML file, but it's not working as it should.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="jquery.chained.min.js"></script>
<script charset=utf-8>
$(function(){
$("#series").chained("#mark");
});
</script>
</head>
<body>
<select id="mark" name="mark">
<option value="">--</option>
<option value="bmw">BMW</option>
<option value="audi">Audi</option>
</select>
<select id="series" name="series">
<option value="">--</option>
<option value="series-3" class="bmw">3 series</option>
<option value="series-5" class="bmw">5 series</option>
<option value="series-6" class="bmw">6 series</option>
<option value="a3" class="audi">A3</option>
<option value="a4" class="audi">A4</option>
<option value="a5" class="audi">A5</option>
</select>
</body>
</html>
Answer
It's common practice to include a jsfiddle when submitting this type of question. See my example here, which works. If you come up with an example that doesn't work, and show us a jsfiddle, we can help much better.
If I had to guess, I'd say your script paths are wrong.
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="jquery.chained.min.js"></script>