Call a Javascript function AFTER the Server Onclick event

Question

I have this code for a click event of a button:

protected void Button1_Click(object sender, EventArgs e)
{
    string message = "";
    //Series of codes to change the message variable

    Page.ClientScript.RegisterStartupScript(GetType(), "", "ShowMessage(" + message +");", true);
    }



<script type="text/javascript">
    function ShowMessage(msg){
        alert(msg);
    }
</script>

and this won't display the message. maybe my RegisterStartupScript is incorrect?

Answer 1

Try followings,

1. You have to give a valid name for your script. http://msdn.microsoft.com/en-us/library/z9h4dk8y.aspx

   A startup script is uniquely identified by its key and its type. Scripts with the same key and type are considered duplicates. Only one script with a given type and key pair can be registered with the page. Attempting to register a script that is already registered does not create a duplicate of the script.

2. ShowMessage should be defined in the page

3. You have to pass the parameter as string. ShowMessage('" + message +"');

4. Final code should like this

Page.ClientScript.RegisterStartupScript(GetType(), "myAlertScript", "ShowMessage('" + message +"');", true);

UPDATE

---

If you have update panels in the page, try following code instead.

ScriptManager.RegisterClientScriptBlock(this,typeof(Page),"myAlertScript","ShowMessage('" + message +"');", true);

Answer 2

在对ShowMessage的调用中，您缺少message变量周围的引号，请尝试以下操作：

Page.ClientScript.RegisterStartupScript(this.GetType(), "", "ShowMessage(\"" + message + "\");", true);

Answer 3

To test if the message is delivered to the client you can simply call a native javascript function that'll rule out any client side issues.

Page.ClientScript.RegisterStartupScript(GetType(), "", "alert('here?');", true);

You can also view the source of a page in your browser to see if the code is being delivered to the client.

Answer 4

To execute code after the click handler (and anything it calls) is complete, set a timeout during the handler.

function onClick() {
    window.setTimeout(functionToCall, 0);
}