But Paul! SharePoint has a client-side object model. Well, yes and no.

Yes. SharePoint has the WPSC to fetch properties about a page’s web parts. However, SharePoint’s JavaScript uses an ActiveX object to call the SharePoint web services–a completely unnecessary strategy that locks you into using IE. No, no, and no.

When I looked at rewriting the WPSC for use in all browsers, I noticed that a lot of the data I wanted was already on the page, just not in a format I could use in my code. So, for starters, I’m not going to call the web service at all.

The CTX object

Every time an out-of-the-box web part with a SP data source loads, it creates another instance of the CTX (context) object. Each one gets a number (ctx1, ctx2, …). These objects hold some good info about the web parts on the page but it’s missing simple stuff like web part title!

Open Firebug and type ctx into the console. You’ll see the last ctx object created and some of the properties it holds.

A better Object

The web parts on your page all get IDs like “WebPartWPQ8″. These are apparently given out at runtime and are therefore subject to change based on the order in which the web parts are loaded and which ones are open (as opposed to closed, not deleted). So they’re useless without a way to map them back to your web part.

I want to provide context for my jQuery selectors to specific web parts and I want to do that by web part title, something with meaning. So I wrote the code below in a jQuery plug-in style to build an object with meaningful names like Tasks, Announcements, and Calendar instead of ctx1, ctx2, and ctx3.

if (typeof wp=='undefined'){ //check for the wp object
	$("div[webpartid]").wpCollect();  //build the wp object
}
if (typeof wp.Pics=='object'){  //check for the specific web part by name
	$("#"+wp.Pics.id).hide(); //hide the Pics web part by ID
}

Since I can also collect the ctx object for a given web part, I put that inside my wp object so I can get at all of the available data by web part title (or guid if the title was hidden by turning Chrome off in the web part settings).

You can get the data from your objects like this: wp.Tasks or by using the bracket notation when names have spaces: wp["Shared Documents"].

<script type="text/javascript">
if(typeof jQuery=="undefined"){
	var jQPath="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/";
	document.write("<script src='",jQPath,"jquery.min.js' type='text/javascript'><\/script>");
}
</script>
<script type="text/javascript">
(function(){
	jQuery.fn.wpCollect = function(){
		wp = {};
		this.each(function(i,e){
			var guid = e.getAttribute("webpartid").toUpperCase();
			var id = e.id;
			var ctx = g_ViewIdToViewCounterMap["{"+guid+"}"];
				ctx = (!ctx)?{}:eval("ctx"+ctx);
			var title = id.replace(/WebPartWPQ/,"#WebPartCaptionWPQ");
				title = $(title);
				title = (title.length==0)?guid:title.prev().text();
			wp[title] = {guid:guid,id:id,ctx:ctx};
		});
		return this;
	};
})();
$(function(){
	if (typeof wp=='undefined'){ //check for the wp object
		$("div[webpartid]").wpCollect();  //build the wp object
	}
});
</script>

Paul Grenier