comp.lang.javascript archive
Re: "Undefined" in scrolling_list
Date: Sat Jan 21 2006 - 12:03:40 CET
William wrote:
> I tried to update a scrolling_list with the following:
>
> function saveText( scroll_list, t_area, listToBeUpdated ) {
> var updated = new Option();
> updated.value = t_area.value;
> updated.text = t_area.text;
> scroll_list.options[scroll_list.selectedIndex] = updated;
> }
>
> but I get "Undefined" in the position with the new Option()
> (i.e. "updated").
>
> Why and how to fix this?
Your code is incomplete, which makes it hard to narrow down the
problem. I'm assuming a "scrolling_list" means a select-tag with size
>1.
How should your "update" action behave ? First empty the box or just
add new text/value pairs ? I'm assuming the first, otherwise just
comment the while loop in the code.
------------------------
<html>
<head>
<script language="javascript">
function saveText() {
// empty box
while (document.forms[0].scroll_list.options.length)
document.forms[0].scroll_list.options[0] = null;
// put new content in the box
document.forms[0].scroll_list.options[document.forms[0].scroll_list.length]
= new Option("brown", "6");
document.forms[0].scroll_list.options[document.forms[0].scroll_list.length]
= new Option("black", "7");
}
</script>
</head>
<body>
<form>
<select size="3" name="scroll_list">
<option value="1">white</option>
<option value="2">blue</option>
<option value="3">green</option>
<option value="4">red</option>
<option value="5">yellow</option>
</select>
<input type="button" value="Update" onClick="saveText();">
</form>
</body>
</html>
-- BartReceived on Tue Feb 7 21:17:12 2006