Textbox value change on select other item dropdownlist

[Atreju]

Ok I got form within a c sharp page.

Situation:
On the form I have a drop downliwst and a textbox, the dropdownlist is
populated with products and the textbox has a default vale of the product
price.

Problem:
The first item prce in the dropdownlist is populated in the textbox.
When I select another product from the dropdownlist the value within the
textbox doesn't change to the price of the selected product.

Question:

Can someone tell me how let the textbox value be changed if another item is
selected from the dropdownlist without having to do a postback(which
immediatly submits the form).

Example data loaded in form:
Productname (loaded in dropdownlist) Productprice (loaded in textbox)
Chocolate chips 1,-
Strawberry 0,50

Is this only possible by building up an javascript array and not by doing
somesort of callback on the page after the ddl item has been selected?
Thanks in advance,
A

[Anmol]

You need to add the below javascript in ur html section of the page

<script language="javas cript">
function ShowValue()
{
document.Form1["textboxnam e"].value =
document.Form1["dropdownva lue"].value
}
</script>
and in the codebehind file add this line

Dropdowncontrol .Attributes.Add ("onchange","ja vascript:ShowVa lue()");

Now when you change the value in the drop down, the Textbox will be
filled without refreshing the page