Evaluating JSON:

var obj = eval('(' + str + ')');

Detecting if someone is pressing ENTER (jQuery is used in the listing):

$container.find("input").keydown(function(event){ 
  if(event.keyCode == 13) 
    saveText($container, $(this)); 
});

Often when creating interfaces with jQuery I end up using something like “key-id” for elements, then the following function is handy for quickly getting just the id part:

function getId(el, sep){
	sep = sep == '-' ? sep : '_';
	var arr = el.attr('id').split(sep);
	return arr[1]; 
}

Opening in a new window/popup:

window.open('http://www.facebook.com/sharer.php?u='+encodeURIComponent(u)+'&t='+encodeURIComponent(t),'sharer','toolbar=0,status=0,width=626,height=436');

Going to a new url in the parent window that opened the current window executing the code:

function openInParent(url){
	window.opener.location.href = url;
}

Getting the current domain:

newArray = window.location.href.match(/^http:\/\/[^\/]+/gi); 
alert(newArray[0]);

Setting and unsetting/clearing a timeout:

twTimeout = setTimeout("displayTwitter()", 60000);
. . .
clearTimeout(twTimeout);

Reloading a window:

window.location.reload();

Analytics tracking:

(function () {
	var req = document.referrer.split('?');
	var body = document.getElementsByTagName('body')[0];
	var img = document.createElement('img');
	var params = req[1].split(/[\?&=]/).join('|');
	img.setAttribute('src', 'http://localhost:8090/req?acc=1&params='+encodeURI(params)+'&ref='+encodeURI(req[0]));
	body.appendChild(img);
})();