Calling Javascript function from Code Behind in C#

Question

I have a javascript function in the External JS File. I want to call it from the co0de behind. How can I do that ? I read somewhere that I can do from ScriptManager.RegisterStartupScript but how, can anyone explain me.

JS File:

    Function1()
    {
      alert("came");
     //Some More logic
    }

Update

Calling from

//Tried this But NOT WORKING
 protected void Page_PreRender(object sender, EventArgs e)
 {
      ScriptManager.RegisterStartupScript(this, GetType(), "Function1", "Function1();", true);
     Page.ClientScript.RegisterStartupScript(GetType(), "Function1", "Function1()", true);

 }

possible duplicate of How to call Jquery function from C#

hackp0int
– hackp0int

2015-05-22 19:28:55 +00:00
Commented May 22, 2015 at 19:28 — hackp0int
– hackp0int, Commented May 22, 2015 at 19:28

stackoverfloweth · Accepted Answer · 2015-05-22 19:27:11Z

1

I've often used this

string script = string.Format("alert('{0}');",alert);
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "Alert", script, true);

basically, it just inserts that line onto your page and runs it as soon as the page loads

answered May 22, 2015 at 19:27

stackoverfloweth

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5 Comments

stackoverfloweth Over a year ago

define alert as what ever variable you want to see show in the alert

hello temp11 Over a year ago

My Function1() is containing some big logic, which I want to reuse also.So I need to keep in the EXt JS FIle.

stackoverfloweth Over a year ago

is Function1() in the code behind? It's a bit trickier to communicate from js-->c#. If that's the case it's easiest to use an ajax function from js

stackoverfloweth Over a year ago

are you trying to pass your entire function to the page? that won't work

hello temp11 Over a year ago

I am just trying to call the function, not pass it.

Pseudonym · Accepted Answer · 2015-05-22 19:28:38Z

0

To strictly answer your question you are looking for something like this:

//Following statement is used to call pre-defined javascript function
protected void btnServerSide_Click(object sender, EventArgs e)
{
    ScriptManager.RegisterStartupScript(this, GetType(), "myFunction", "myFunction();", true);            
}

Here is a site that provides some more details and examples

MSDN also has a great walkthrough with multiple examples

This is my favorite of the walkthroughs listed above, it is very comprehensive

answered May 22, 2015 at 19:28

Pseudonym

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1 Comment

Pseudonym Over a year ago

Probably because your trying to call javascript before it is even processed, notice how mine fires off of a button click and you have yours within a prerender function

Sachu · Accepted Answer · 2015-05-22 19:58:00Z

0

you can try

ClientScript.RegisterStartupScript(GetType(),"CallMyFunction","Function1();",true);

OR

ClientScript.RegisterStartupScript(this,this.GetType(),"CallMyFunction",
                                     "Function1();",true);

another approach is

ScriptManager.RegisterStartupScript(Page, typeof(Page), "somekey", script, true);

this will works during partial postbacks also.

edited May 22, 2015 at 19:58

answered May 22, 2015 at 19:27

Sachu

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2 Comments

Sachu Over a year ago

@hellotemp11 try this.GetType() instead of this, GetType()

Sachu Over a year ago

@hellotemp11 also try by putting an alert instead of function1() place and check is it working

Damith · Accepted Answer · 2015-05-22 20:07:58Z

0

sample code, which will include javascript file and then call method from the code behind.

MyJSFile.js

function Test() {
    alert("hi");
}

WebForm1.aspx.cs -

 using System;
using System.Web.UI;
using System.Web.UI.HtmlControls;

namespace CodeprojectTest
{
    public partial class WebForm1 : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            var js = new HtmlGenericControl("script");
            js.Attributes["type"] = "text/javascript";
            js.Attributes["src"] = "JScript1.js";
            Page.Header.Controls.Add(js);
            Page.ClientScript.RegisterStartupScript(this.GetType(), "myScript", "Test();", true);
        }
    }
}

answered May 22, 2015 at 20:07

Damith

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1 Comment

hello temp11 Over a year ago

Is the "script" and "myScript" should be same ? Why have you used those 2 variables here ?

ANJYR · Accepted Answer · 2015-05-22 19:30:17Z

-1

You may try this..

Page.ClientScript.RegisterClientScriptBlock(typeof(Page), "CallMyFunction", "myFunction()", true);

answered May 22, 2015 at 19:30

ANJYR

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