I find putting the script files at the end to be invaluable from a performance standpoint. This also ties in with making the site degrade gracefully for those who still have javascript disabled.
The site looks and works fine with no javascript at all. Once the page has been rendered, the script files are downloaded and activated to improve the user experience. Because I've stayed away from having the javascript redraw elements on first load, there are no unnatural jumps or flickers when the javascript does load. I've done some testing on a 56k modem with putting the scripts in the head, and there is a significant performance hit on the page being available to the user. Personally I've become a convert and not try to put all scripts at the bottom whenever possible. JK -----Original Message----- From: jquery-en@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jake McGraw Sent: Tuesday, April 08, 2008 9:20 AM To: jquery-en@googlegroups.com Subject: [jQuery] Re: $(window).bind("load",function(){ vs onready >From the comments on Yahoo Performance Rule # 5 http://developer.yahoo.net/blog/archives/2007/07/high_performanc_5.html: :: snip :: There are some cases where you wouldn't want your JS at the bottom. For example, if you were using an "ondomready" event that many of the js libraries supply, you would want the code to execute towards the top. If you were to move all your JS to the bottom of the page, the event would be rendered useless. However, it's nice to know that having it at the top is a performance hit so that I can weigh the positives with the negatives before moving forward. :: snip :: So there is an instance where, using jQuery $(document).ready() or any JavaScript library DOM ready functionality, it makes more sense to keep your script tags in the document head. In the end, it's up to the developer which method to use, as both can be utilized successfully. I said in my original post that this is mostly the territory of debate for "standardistas", therefore its worth inside of real-world web application development is questionable. Considerations of end user experience often override whatever the W3C or ECMA specificies. I'm just providing an alternate opinion so developers can make an informed consideration. Thankfully, jquery-en provides a professional environment where we can have this discussion. - jake On Tue, Apr 8, 2008 at 11:40 AM, Mika Tuupola <[EMAIL PROTECTED]> wrote: > > > On Apr 8, 2008, at 6:23 PM, Jake McGraw wrote: > > > > Regardless of whether it validates, it's considered best practices to > > keep all <script> tags out of the body: > > > > It all depends who "consideres". > > http://developer.yahoo.com/performance/rules.html#js_bottom > > > > > If you put your scripts at the very end of a page, it is possible that > > a user already sees part of the page including a button with a > > JavaScript function call, while the rest of the page hasn't loaded > > yet. Result: user pushes button and gets JavaScript Error Message > > Alerts, because the browser can't find the script (yet). > > > > > True, if you do things like: > > <input type="button" onclick="checkform()" /> > > Then again not a problem if you write unobtrusive JavaScript. > > $(function() { > $("input").bind("click", checkform); > }); > > And isn't jQuery about writing unobtrusive JavaScript? ;) > > > > -- > Mika Tuupola > http://www.appelsiini.net/ > >
