If you use jQuery, you don’t need it. But if you for some reason must use javascript you must beware of adding events. The most dangerous is window.onload. Consider this scenario:

function doSomethingGreat() {};
window.onload = doSomethingGreat;
```It works fine if you are the only person who writes window.onload handler. But on such platforms like SharePoint you can't know which events exist. And if you just write **window.onload = doSomethingGreat;** you override all other window.onload events. Again, in jQuery you have nothing to worry. jQuery(window).load(doSomethingGreat) will just add your event, not override. In this post I'll show how to extend an event handler the pure javascript way. We have to create our own function for adding event handlers. First the old events have to be temporary saved and then the new event has to be added. [Like this](http://jsfiddle.net/mirontoli/cnN6s/):

function addOnclick(elem, func) { var old = elem.onclick; if (typeof elem.onclick != ‘function’) { elem.onclick = func; } else { elem.onclick = function () { if (old) { old(); } func(); };
} }

To sort an array in javascript, just run sort():

array = \["skåne", "blekinge", "halland"\];
array.sort();
```To [perform a more intelligent sorting](http://stackoverflow.com/questions/3859239/sort-json-by-date "See the original answer in stackoverflow") we can define our sorting logic. What if an array has objects with different properties? For example, an object has title and lastupdated. We want to sort on lastupdated. Just create a function for this with two parameters:

function custom_sort(a, b) { return new Date(a.lastUpdated).getTime() - new Date(b.lastUpdated).getTime(); }

Javascript is very fast, responsive and unburdens the cpu at the server. Here I show a little example how to use jQuery.getJSON, jQuery.tmpl (wonderful plugin for rendering repeating data, repo hosted on Github) and REST-based service listdata.svc from /_layouts/_vti_bin/ folder. For this example I created a generic list “Contacts”, added two text fields Name and Phone. Add some phone numbers and try to go to /_vti_bin/ListData.svc/Contacts If you get 404-error, install a ADO.NET Data Services v1.5 CTP2, as described at dotnetmafia. If you want to know more about how to sort and filter, skip and limit results, read more at nothingbutsharepoint. If you encounter problems, follow Michaël’s blog post and download and install Windows6.1-KB976127-v6-x64.msu (if you have Windows Server 2008 R2), or NDP35SP1-KB976126-v2-x64.exe (if you have Windows Server 2008). After installing the version of the System.Data.Services.dll file is 3.5.30729.5004 (Windows Server 2008 R2), and 3.5.30729.4466 (Windows Server 2008). Allright, the remainder is pure javascript. In order to get it working you have to run the script from the same domain, meaning you can’t run javascript to retrieve the data from a html-file from your home folder. Create a webpart and add it to your page.

Well, if you need remove links to user profiles, you can iterate all td-elements with class ms-vb-user using jQuery each function and remove a elements. Here is a little script:

$(document).ready(function() {
	$(".ms-vb-user a").each(function() { 
	   var text = $(this).text(); 
	   var span = document.createElement("span"); 
	   var user = document.createTextNode(text); 
	   span.appendChild(user); 
	   var parent = $(this).parent()\[0\]; 
	   parent.removeChild(this); 
	   parent.appendChild(span); 
	});
});
```EDIT 2012-02-05 A much more better way to do it is [to use replaceWith in jQuery](http://stackoverflow.com/a/2409163/632117 "See a similar question and an answer on StackOverflow"):

$(".ms-vb-user a").each(function() { $(this).replaceWith(this.childNodes); });

Favicon is one of the hardest. Ctrl-F5 doesn’t help. You can of course see the source, find the location of the favicon, click on it (if you use Firefox or Chrome), otherwise copy the url and paste it in the address bar. When you load it separately, the favicon cache is renewed. It works. But if you want to make it easier for your users, set a version to your favicon file in the masterpage:

Add link for “Go Back” in javascript (inspired by Webmasters tips):

<a href="javascript:location.href=document.referrer;">Back</a>
```If you have access to the code behind you can [do the same](http://www.beansoftware.com/ASP.NET-FAQ/Referrer-URL.aspx) with:

Request.UrlReferrer.ToString() ```If you want to go to site collection root, it is simple, too: <SharePoint:SPLinkButton runat="server" NavigateUrl="<% $SPUrl:~SiteCollection/%>">Start</SharePoint:SPLinkButton>

If you have a master page with fixed size (perhaps in a centered layout). Here is a simplistic js-script to auto-resize:

$(window).load(function(){
	$wider = false;
	$pagecontainer = $("#pagecontainer");
	$elementsToCareAbout = $("#ctl00\_MSO\_ContentDiv > \*, #ctl00\_MSO\_ContentDiv table")
	$elementsToCareAbout.each(function(){
		if($(this).width() > $pagecontainer.width())
		{
			$wider = true;
		}
	});
	if ($wider) $pagecontainer.width(1200);
});

Any improvement ideas and suggestions are more than welcome.

Well, sometimes we need to calculate width and so on. In my next post I will write about how to fix auto-resize on fixed sized master pages. But now: a very nice stuff: how to check if an element is hidden or not:

$("#s4-leftpanel").is(":visible")
```It is a pure poetry. It reminds me of the beauty of [symbols in Ruby](http://rubylearning.com/satishtalim/ruby_symbols.html).

Are you also curious about NoSQL databases. Well, MongoDB is one of the most known ones. MongoDB has a javascript syntax (json), I like it. Try out the interactive shell at the mongodb site.

Quickstart on Ubuntu

To test it on Ubuntu, just install an existing apt-package:

sudo apt-get install mongodb

Create the default folder and change permissions:

SP.js exists in two variants in debug mode and in modified. When you develop it is better to use debug mode. When it goes to production it is better to use minified files. The same you can do with your files. Wictor Wilen explains how to do minify your custom javascript files. I think it is a good pattern to create javascript files and call them something-something**.debug.js**. Then when you are done, run the custom tools to minify them.