How do I pass the value of the previous form element into an "onchange" javascript function?
- by Jen
Hello,
I want to make some UI improvements to a page I am developing. Specifically, I need to add another drop down menu to allow the user to filter results.
This is my current code:
HTML file:
<select name="test_id" onchange="showGrid(this.name, this.value, 'gettestgrid')">
<option selected>Select a test--></option>
<option value=1>Test 1</option>
<option value=2>Test 2</option>
<option value=3>Test 3</option>
</select>
This is pseudo code for what I want to happen:
<select name="test_id">
<option selected>Select a test--></option>
<option value=1>Test 1</option>
<option value=2>Test 2</option>
<option value=3>Test 3</option>
</select>
<select name="statistics" onchange="showGrid(PREVIOUS.name, PREVIOUS.VALUE, THIS.value)">
<option selected>Select a data display --></option>
<option value='gettestgrid'>Show averages by student</option>
<option value='gethomeroomgrid'>Show averages by homeroom</option>
<option value='getschoolgrid'>Show averages by school</option>
</select>
How do I access the previous field's name and value? Any help much appreciated, thx!
Also,
JS function for reference:
function showGrid(name, value, phpfile)
{
xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
{
alert ("Browser does not support HTTP Request");
return;
}
var url=phpfile+".php";
url=url+"?"+name+"="+value;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChanged;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}
