Javascript works on page and not working if referenced

Question

4.00/5 (2 votes)

See more:

Hi,
I want to read a property from the code behind in my javascript on load, and i am doing it happily like this:

<script language="javascript">
    $(window).load(function() {
        if ('<%= IsNewRecord %>' == 'True') {
            alert("new record");
        }
    });
</script>

where property 'IsNewRecord' is in my code behind like below:

protected bool IsNewRecord
   {
       get { return true; }
   }

It works fine till here, but when i move my javascript code to a external file say test.js and reference it in my script tag on the page, the behaviour stop working with no errors.

<script src="scripts/test.js" type="text/javascript"></script>

Why ?

Posted 26-May-11 16:03pm

saxenaabhi6

Updated 26-May-11 16:23pm

thatraja

v2

Add a Solution

Comments

Wonde Tadesse 26-May-11 22:44pm

How do you know it's referenced correctly ? Have you tried to call another function or ?

saxenaabhi6 26-May-11 22:56pm

i did put an alert on the top of my external test.js its
alerting that.

Wonde Tadesse 26-May-11 23:22pm

Good to know that at least something is working :). See Yvan Rodrigues or --SA answer.

saxenaabhi6 26-May-11 23:35pm

Thats called bog down, i should have stuck to the 'on page js' and moved forward :P

Yvan Rodrigues 27-May-11 8:10am

We've all done that many, many, many times. It's a good thing (in small doses). It's lazy to just accept that something works if it could be better. A Ford Escort works. A Porsche Carrera is fast and beautiful.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Yvan Rodrigues · Accepted Answer · 2011-05-26T16:45:00

When a web browser wants a web page it issues an HTTP GET to the server for the html file, or in this case, your aspx file. The web server, in this case IIS, knows that the file that the client requested is an ASP.NET web form by identifying the .aspx file extension. It uses that as a cue that it needs to execute the dynamic content in your web form, and send the output to the TCP stream.

When the client browser receives your HTML, it parses it, and makes a list of all external resources in the HTML such as CSS, images, and your javascript. It then issues a separate HTTP GET for each of those resources. Once it has received them all it assembles and renders the page to the user.

In that previous step the browser made a request for your .js file. The server received the request and happily delivered the javascript to your browser. Since the file extension is .js, not .aspx it didn't know that you wanted it to parse the javascript and look for your codebehind reference. It just delivered the goods.

You have three options.

1. Just embed the javascript in the html file like you did originally.

2. Rename the standalone javascript file to a .aspx extension and in the .aspx add a ContentType @Page directive[^] to text/javascript. In your HTML, link to the .aspx file.

<script src="scripts/test.aspx" type="text/javascript"></script>

IIS will now parse and compile your javascript document, correctly rendering your codebehind; since the MIME content type is correctly set, the browser will treat it as javascript, even though it has a .aspx extension.

3. In the IIS configuration (or web.config) you can configure IIS so that it treats all .js files as web forms.

How nice, THREE options!

Sergey Alexandrovich Kryukov · Accepted Answer · 2011-05-26T16:37:00

Solution 1

Isn't it obvious? Look at the part '<%= IsNewRecord %>'. This part of code is not Javascript. It is generated by your code behind, so your page is generated with either

JavaScript

if ('True' == 'True') {
    alert("new record");
}

or

JavaScript

if ('False' == 'True') {
    alert("new record");
}

So, Javascript code is generated dynamically depending on that IsNewRecord returns and results in valid Javascript code, one or another, different on each HTTP request.

When you put this file outside of you *.ASPX file, the code is delivered on the request for the same page as is, which is not a valid Javascript code. Javascript interpreter fails, your server hides error processing (which is the normal option for production), so you simply don't get your processing.

—SA

Posted 26-May-11 16:37pm

Sergey Alexandrovich Kryukov

Updated 26-May-11 17:38pm

v3

Comments

Yvan Rodrigues 26-May-11 22:51pm

I concur :)

saxenaabhi6 26-May-11 23:00pm

hmmm.... I got what you said but i was thinking that aspx page will load properties first and then might load javascript file resolving the property...
any ways to set loading preferences.

Sergey Alexandrovich Kryukov 26-May-11 23:35pm

What you're talking about has nothing to do with ASP.NET. The page is generated on HTTP request, client's browser reads HTML file which is pure HTML and sees the resource to be loaded in an external file. This is another HTTP request which delivers the file.
--SA

saxenaabhi6 26-May-11 23:38pm

yaa go it.... the js will come just like a banner image, no processing once rendered.. Thanks :) my 5

Sergey Alexandrovich Kryukov 26-May-11 23:55pm

You're welcome.
If you got it, will you please formally accept the answer (green button)?
--SA