使用参数从JavaScript调用CodeBehind方法

Question

I'm trying to call a code behind method from JavaScript code. This works fine, but I am not sure how can I pass a JavaScript parameter to the method. If I put any value between the parenthesis, it is related as a CodeBehind context rather then script context. What is the solution to pass this parameter?

JavaScript:

var arg = this.id
<% setSelection(arg); %>   

C#:

[WebMethod]
public void setSelection(string productID)
{
   Session["selection"] = productID
}

I get this error of course: CS0103: The name 'arg' does not exist in the current context

Answer 1

Your setSelection(arg) call is not calling the code behind from JavaScript. It is getting called on the server side, before the HTML response is even output to the browser, way before the JavaScript executes. Also the arg is treated as a C# variable.

If you want to make the call from JavaScript, you need to use AJAX. See this example .