Add this to your .vimrc:

autocmd FileType python set omnifunc=pythoncomplete#Complete
autocmd FileType javascript set omnifunc=javascriptcomplete#CompleteJS
autocmd FileType html set omnifunc=htmlcomplete#CompleteTags
autocmd FileType css set omnifunc=csscomplete#CompleteCSS
autocmd FileType xml set omnifunc=xmlcomplete#CompleteTags
autocmd FileType php set omnifunc=phpcomplete#CompletePHP
autocmd FileType c set omnifunc=ccomplete#Complete

Try it out:

$ touch index.html
$ vim index.html
type: <ht[CTRL-X][CTRL-O]

Take the location, convert to string, and split twice:

vidID = document.location.toString().split("v=")[1].split("&")[0];

JSON is an acronym for JavaScript Object Notation.

var myobj = new Object();
myobj.prop = 1;

var myobj = {prop:1};

var a = new Array();
a[a.length] = 1;
a[a.length] = 2;

var a = [1, 2];

I had written this greasemonkey script in order to create _blank links. It'll work most anywhere you need this kind of thing:

var allLinks, thisLink;

allLinks = document.getElementsByTagName('a');

for (var i = 0; i < allLinks.length; i++) {
    thisLink = allLinks[i]; thisLink.target = '_blank';
}