Prepopulate fields in SharePoint with Querystring values via Jquery

What are you talking about?
Paul Grenier over at EndUserSharePoint discussed in length a lot of great stuff you can do with Jquery and SharePoint. This is one of the really cool things I used at a client:
This code is used to prepopulate values you put in the querystring into SharePoint fields. This is really useful for when you link to create an item, and need to have some default values filled in depending on the link. You click on the link and go to a page where some fields are allready filled in. This is also great to create linked items in SharePoint via RootFolder and ID fields.

So how does this work ?
1. Add the standard Jquery file to a document library on your site (you can also directly link to the ajax google file (http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/)
2. Add the script on the SharePoint page where you want to prepopulate the fields, like the new or edit form
3. Create a link to that page containing some querystring parameters.
IMPORTANT: the querystring parameters have to have the same name as the fields you want to prepopulate !!
For those non-techies: The link has to look like this: http://www.yoursite/page.aspx?parameter1=xxxx&parameter2=yyyy&parameter3=zzzz
All done, click on the link and watch the fields being prepopulated 🙂

The script

/*
 * Prepopulate form fields in SharePoint
 * Copyright (c) 2008 Paul Grenier (endusersharepoint.com)
 * Licensed under the MIT (MIT-LICENSE.txt)
 */
(function(){
	var params = window.location.search.substring(1).split("&"),
		kv = {},
		opts,
		sp=/%20|\+/g,
		datetime=/([1-9]|0[1-9]|1[012])[\-\/.]([1-9]|0[1-9]|[12][0-9]|3[01])[\-\/.](19|20)\d\d\s([0-1][0-2]|[0-9]):([0-9]{2})\s(A|P)M/i,
		date=/([1-9]|0[1-9]|1[012])[\-\/.]([1-9]|0[1-9]|[12][0-9]|3[01])[\-\/.](19|20)\d\d/,
		clean = function(str){
			return str.replace(sp," ");
		},
		getKv = function(){
			$.each(params,function(i,e){
				var p=e.split("=");
				kv[p[0]]=decodeURIComponent(p[1]);
			});
			return kv;
		};
	jQuery.prepop = function(){
		$.each(getKv(),function(k,v){	
			k=clean(k);
			v=clean(v);
			var f=$("[title='"+k+"']"),
				job;
			if (f.length>0){
				if (f[0].type=="text"){job=10;} //text
				if (f[0].type=="checkbox"){job=20;} //checkbox
				if (f[0].tagName=="SPAN"&&f.hasClass("ms-RadioText")){job=30;} //radio
				if (f[0].type=="select-one"&&f[0].tagName=="SELECT"){job=10;} //choice and non-IE lookup
				if (f[0].tagName=="TEXTAREA"){job=10;} //textarea
				if (f[0].type=="text"&&f[0].opt=="_Select"){job=70;} //IE lookup
				if (v.match(date)){job=40;} //date
				if (v.match(datetime)){job=50;} //datetime
			}
			if (f.length===0){ 
				var elm = $("nobr:contains('"+k+"')");
				if (elm.length>0){
					elm = elm.parents("td").next()[0];
					var s1 = $(elm).find("select:first"),
						s2 = $(elm).find("select:last"),
						p1 = $(elm).find("textarea[title='People Picker']"),
						p2 = $(elm).find("div[title='People Picker']"),
						vals = v.split(",");
					if (s1.length>0){job=80;} //multi-select
					if (p1.length>0){job=90;} //people picker
				}
			}
			switch (job){
			case 10:
				if (v.substring(0,1)=="@"){
					opts = f[0].options;
					$.each(opts,function(i,e){
						if (opts[i].value==v.substring(1)){f[0].selectedIndex=i;}
					});
				}else{
					f.val(v);
				}
				break;
			case 20:
				if (v.toUpperCase()=="TRUE"||v=="1"){f[0].checked=true;}
				if (v.toUpperCase()=="FALSE"||v=="0"){f[0].checked=false;}
				break;
			case 30:
				if (v.toUpperCase()=="TRUE"||v=="1"){f.find("input:radio").click();}
				break;
			case 40:
				v=v.replace(/[\-\/.]/g,"/");
				f.val(v);
				break;
			case 50:
				var dt=v.split(" "),
					d=dt[0].replace(/[\-\/.]/g,"/"),
					t=dt[1],
					hm=t.split(":"),
					hh=hm[0].replace(/^0/,""),
					mm=hm[1],
					ap=dt[2].toUpperCase();
				f.val(d);
				f.parent("td").siblings("td.ms-dttimeinput")
					.find("select:first").val(hh+" "+ap)
					.parent("td").find("select:last").val(mm);		
				break;
			case 70:
				if (v.substring(0,1)=="@"){
					ShowDropdown(f[0].id);
					opts = $("#_Select")[0].options;
					$.each(opts,function(i,e){
						if (opts[i].value==v.substring(1)){$("#_Select")[0].selectedIndex=i;}
					});
					f.blur();
				}else{
					f.val(v);
					ShowDropdown(f[0].id);
					f.blur();
				}
				break;
			case 80:
				opts = s1[0].options;
				$.each(vals,function(i,e){
					var V=e;
					$.each(opts,function(i,e){
						if (opts[i].text==V){
							s2.append("<option value='"+opts&#91;i&#93;.value+"'>"+V+"</option>");
						}
						if (V.substring(0,1)=="@"){
							if (opts[i].value==V.substring(1)){
								s2.append("<option value='"+V+"'>"+opts[i].text+"</option>");
							}
						}
					});
				});
				break;
			case 90:
				var p=vals.join(";");
				p1.val(p);
				p2.html(p);
				break;
			//default:
			}
		});
	};
})();
$(function(){
	$.prepop();
});
</script>