add values to dropdown list

[soni2926]

hi,
I'm trying to add some values to a dropdown list via javascript, but i
keep getting this error:
sControl.options is undefined

here is the code below:
var sControl = document.getElementById
('ctl00_ContentPlaceHolder1_ddl2');
var totalSize = result.length;

var opt = document.createElement("option");

for (var i = 0; i < totalSize; i++) {
sControl.options.add(opt);
opt.text = "something";
opt.value = "123";
}

if i use firebug (firefox js debugger plugin) it shows that it picks
up sControl as type select-one, am i adding it wrong to the
dropdownlist?

 

[Thomas 'PointedEars' Lahn]

I'm trying to add some values to a dropdown list via javascript, but i
keep getting this error:
sControl.options is undefined

here is the code below:
var sControl = document.getElementById
('ctl00_ContentPlaceHolder1_ddl2');

Looks like a rather clueless approach to get a form control.
Brush up on the `elements' collection (discussed here ad nauseam).

var totalSize = result.length;

Good idea, however you should consider to declare more than one loop-related
variable in the initialization part of the `for' statement:

for (var i = 1, j = 2, k = 3; ...; ...)

That is not related to block scoping but it shows more clearly where a
variable is used.

var opt = document.createElement("option");

Not so good an idea. Use the proprietary, but better supported

var opt = new Option("text", "value");

instead.

for (var i = 0; i < totalSize; i++) {
sControl.options.add(opt);

See above. Do it the standards-compliant *and* backwards-compatible way
instead:

var opts = sControl.options;
opts[opts.length] = opt;

instead.

opt.text = "something";
opt.value = "123";

Although it could work, this statement order makes little sense. I
recommend (with exceptions) to assign the properties first, then append the
child element (object).

}

if i use firebug (firefox js debugger plugin) it shows that it picks
up sControl as type select-one, am i adding it wrong to the
dropdownlist?

Probably your markup is not Valid. A `select' element MUST contain at least
one `option' element in the first place.

<http://validator.w3.org/>


PointedEars

 

[SAM]

Le 11/24/08 10:02 PM, soni2926 a écrit :

hi,
I'm trying to add some values to a dropdown list via javascript, but i
keep getting this error:
sControl.options is undefined

here is the code below:
var sControl = document.getElementById('ctl00_ContentPlaceHolder1_ddl2');

and there, at this step :
alert(sControl);
does it say 'undefined' ?

if yes, probably your select has no ID ?!

var totalSize = result.length;

var opt = document.createElement("option");

for (var i = 0; i < totalSize; i++) {

sControl.options = new Option("something", "123");
}

sControl.options.add(opt);
opt.text = "something";
opt.value = "123";
}

if i use firebug (firefox js debugger plugin) it shows that it picks
up sControl as type select-one,

and then ?
that doesn't tell if it has an ID ...