Question

I need to call a javascript function when the dropdown list is changed.

How can I implement that in asp.net?

Answer 1

<asp:DropDownList runat="server" ID="DDList" onclick="alert(1)"></asp:DropDownList>

If you want to get function executed when element clicked, you can use above code to define a function that should be executed ‘onclick’.

But it is better to use something like addEventListener, just search for cross-browser function (for instance, like addListener function here):

document.getElementById("<%=DDList.ClientID %>").addEventListener("click", fucntionToExecuteName, false)

Remember, than in this case you must take DDList.ClientID and use it as id of an element, because it will be different from ID you have set in your aspx code

But if you need some function to be executed when actual value is changed, you should use onchange event.