使用Ajax刷新Javascript下拉框

Question

I have a question regarding ajax, I have a category drop down box and some javascript in place so that when the user selects a category, this automatically redirects the page to that category without having to click a submit button. My question is simple, how can I add ajax to this process to stop the page load and just load the div with the category items?

I am using expression engine cms, which I know doesn't matter but the tags are in the code.

This is my code:

<script language="JavaScript" type="text/javascript">
    var theTarget = "_top";
    function goThere() {
        if (!document.theForm.theMenu.selectedIndex=="") {
            window.open(document.theForm.theMenu.options[document.theForm.theMenu.selectedIndex].value, theTarget,"");
        }
    }
</script>

<form name="theForm" action="">
    <select name="theMenu" size="1" onchange="goThere()">
        {exp:channel:categories channel="store" style="linear" category_group="1"}
            <option value="{path='store-directory'}">{category_name}</option>
        {/exp:channel:categories}
    </select>
</form>

Answer 1

Use JQuery's $.ajax function to replace the <option> tags within the select based on an ajax callback. The script being called via Ajax would simply return <option> markup ready to be loaded right into the <select>

Take a look at the $.ajax method with JQuery.

http://api.jquery.com/jQuery.ajax/

Answer 2

<script>function goThere(val)
{
    $.post(val, function(data) {
      $("#categoryDiv").html(data);
});
}</script>


<form name="theForm" action="">
<select name="theMenu" size="1" onchange="goThere(this.value)">
{exp:channel:categories channel="store" style="linear" category_group="1"}
<option value="{path='store-directory'}">{category_name}</option>
{/exp:channel:categories}
</select>
<div id="categoryDiv">
</div>
</form>