ansaurus

Question

How to best control loading of multiple javascript files in ASP.NET?

Answer 1

+1 A:

In the control's Page_Load method, you can register your javascript for output (after confirming that it's not already registered).

E.g.,

ClientScriptManager script = Page.ClientScript;
if (!script.IsClientScriptIncludeRegistered("AlertHello"))
{
    script.RegisterClientScriptInclude("AlertHello", "Public/AlertHello.js");
}

NOTE: You can use .RegisterClientScriptBlock() if you want to have a block of JS instead of a separate file.

However, this outputs the script tag soon after the opening of the page's form tag. To output your script near the end of the page (i.e., just prior to the closing of the form tag), use the .RegisterStartupScript() methods.

ClientScriptManager script = Page.ClientScript;
if (!script.IsStartupScriptRegistered("StartupAlert"))
{
    script.RegisterStartupScript(this.GetType(), "StartupAlert",
           "<script type='text/javascript' src='Public/Alert.js'></script>");
}

Supposing that you absolutely need it in a specific place, however, you could add a static (or "shared" in VB.NET) read-only property that returns the script tag, and a boolean property that tells the control whether to output the script tag. In that case, in your ASPX, you could do something like...

<body>
  <!-- any place -->
  <uc1:myControl ID="myControl1" runat="server" jsOutput="False" />
  <!-- elsewhere -->
  <asp:Literal ID="litJS" runat="server" OnLoad="litJS_Load" />
</body>

Then program litJS_Load to set the sender's Text property to the string returned by the static property of the myControl class.

David 2009-04-09 09:00:21

Answer 2

A:

As mentioned using the script registration via the controls' Load event is a good idea, if they are compiled controls, you can also reference them as an embedded resource... If you are using ASP.Net Ajax, you can use the ScriptManager which can merge scripts within your page into one contiguous block for download.

Yahoo has a lot of information regarding script performance as well, the advice for this is also included in the YSlow extension for Firefox, which extends firebug.

In addition to having the scripts as an external resource, you should enable compression on the server, which can reduce download of various scripts. Not to mention minification of included scripts.

Tracker1 2009-04-09 19:03:13

ansaurus

tags:

views:

answers:

How to best control loading of multiple javascript files in ASP.NET?

related questions