Using server side method in an external JavaScript file

In a c# aspx proj开发者_JAVA百科ect. I can reach a static method on client side with importing my namespace at the beginning part of the page, as follows.

<%@ Import Namespace="utl=portal.library.Utilities" %>

And than in can use that on client side of the same asxp page like.

<script type="text/javascript">
var categoryPage;
categoryPage = '<%= utl.getcategoryName().ToString() %>';
</script>

My question is, can i use that '<%= utl.getcategoryName().ToString() %>' in an external javascript file ?

Is it possible something like that ?

<%@ Import Namespace="utl=portal.library.Utilities" %>
<script src="/scripts/trial.js" type="text/javascript"></script>

and in the trial.js file

var categoryPage;
categoryPage = '<%= utl.getcategoryName().ToString() %>';

thanks in advance..

I don't think so, because the external .JS file wouldn't be processed by ASP.NET and therefore wouldn't have access to those kinds of variables.

I don't think you can but you could instead try to pass the server side variable as a parameter to a JS function in the external JS file.

You can create a .aspx file that only outputs Javascript instead of HTML. As long as you set the Content Type to application/x-javascript in the code behind, it will work.

For example, create Test.js.aspx. Then, in the code behind for Test.js.aspx.cs:

protected void Page_Load( object sender, EventArgs e )
{
    Response.ContentType = "application/x-javascript";
}

protected string GetMessage()
{
    return "Hello, World!";
}

In the Test.js.aspx file:

window.onload = function() { 
    var msg = <%=GetMessage() %>
    alert(msg); 
}

Now, it is true that the Javascript running on the client can't call C# functions running on the server. You would need AJAX for that. But you can certainly use this pattern to generate Javascript that make use of ASP.NET when it is generated.