How we can call javascript function from code-behind in asp.net?

Question

I have this javascript function :

function showLoader() {
           document.getElementById("loaderState").style.display = 'inline';
       }

And I have a button :

<asp:Button ID="btnSignUp" runat="server" Text="Sign Up" OnClick="btnSignUp_Click" />

I am tryong to call that js function in code behind :

protected void btnSignUp_Click(object sender, EventArgs e)
{
    try
    {
        int i = users.AddNewUser();
        if (i != 0)
        {
            Page.ClientScript.RegisterStartupScript(
                GetType(),
                "btnSignUp",
                "showLoader();",
                true);
        }
    }
    catch (Exception exp)
    {
        throw exp;
    }
}

But not worked!!! Why?
Thanks.

Have you tried to comment everything in `btnSignUp_Click`, then add just this line: `Page.ClientScript.RegisterStartupScript(GetType(), "btnSignUp", "showLoader();", true);` ? Maybe it's because the `i` value is 0 — ekad, Jan 18 '14 at 13:12
possible duplicate of [Execute javascript function after asp.net postback without Ajax](http://stackoverflow.com/questions/320999/execute-javascript-function-after-asp-net-postback-without-ajax) — Amir, Jan 18 '14 at 18:47
i was used update panel. if use onclientclick="showLoader()" it work fine, but if call it from code behind it does not work. — Farzaneh Talebi, Jan 18 '14 at 19:09
@farzaneh_t: first: you don't explain about `UpdatePanel`. second: i tested your codes without `UpdatePanel`. — Amir, Jan 18 '14 at 19:25
Sorry, I realized why my code does not work. I had used Response.Redirect after calling the JavaScript function. — Farzaneh Talebi, Jan 19 '14 at 13:36

score 2 · Answer 1 · edited May 23 '17 at 12:29

2

Use:

 ScriptManager.RegisterStartupScript(
 this,
 GetType(), 
"btnSignUp",
"showLoader();",
 true);

See these similar question:

ScriptManager.RegisterStartupScript code not working - why?

ClientScript.RegisterStartupScript not working

ScriptManager.RegisterStartUpScript(...) not working

edited May 23 '17 at 12:29

Community

1
1

answered Jan 18 '14 at 12:59

score 1 · Answer 2 · answered Jan 18 '14 at 12:58

Try This

protected void btnSignUp_Click(object sender, EventArgs e)
{
    try
    {
        int i = users.AddNewUser();
        if (i != 0)
        {
ScriptManager.RegisterStartupScript(this, GetType(), "btnSignUp", "showLoader()", true);

        }
    }
    catch (Exception exp)
    {
        throw exp;
    }
}

How we can call javascript function from code-behind in asp.net?

2 Answers2