I'm getting a blank option in my dropdownlist

[MayoorPatel]

Hi there I have a javascript array which is populated by the database

<script language="Javascript" type="text/javascript">
<!--
var subTextArray = new Array();
var subValueArray = new Array();
subTextArray[4] = new Array();
subValueArray[4] = new Array();
subTextArray[4][1] = "4.1 Agriculture1";
subValueArray[4][1] = 122;
subTextArray[4][3] = "4.3 Agriculture3";
subValueArray[4][3] = 123;
//-->
</script>

as you can see the array has been populated with 2 elements from the db and they are indexed 4.1 and 4.3 because I deleted 4.2 earlier. The code that reads these arrays and puts together the actual dropdown is here.

[/code]
<script type="text/javascript">
function populate(catSelect,formName,subSelectName,selected)
{
subSelect = eval("document.forms." + formName + "." + subSelectName);
subSelect.options.length = 0;
var catNum = catSelect.options[selected].value;

if (subTextArray[catNum] == null)
{
var noneOption = new Option("-- No Subcategories --", "-1");
subSelect.options[0] = noneOption;
return;
}

var allOption = new Option("-- Choose a Subcategory --", "-1");
subSelect.options[0] = allOption;
for (var i = 1; i < subTextArray[catNum].length; i++)
{
// there might be blank ones, so skip them out
if (subTextArray[catNum] != null)
{
var tmpOption = new Option(subTextArray[catNum], subValueArray[catNum]);
subSelect.options = tmpOption;
}
}
}
</script>
[/code]

as you can see it loops through the arrays and outputs the dropdown. However Because I deleted 4.2 earlier the code does not take account of this and produces this.

http://www.mayoor.co.uk/dropdowns.jpg

which causes me major problems later on, not to mention the fact it looks ugly. Can anyone help me understand how I could ammend my code so that it cuts out the blank lines?

Mayoor

 

[rac2]

Try testing typeof array element for "undefined" instead of null

if ( typeof subTextArray[catNum][i] == "undefined" ) {
  //skip this one
} else {
  //create this one
}