A quick way to check for the running version of jQuery in your code:

if (jQuery.fn.jquery < '1.3.2')
console.log('yes');  

jQuery has done it again with a very succinct function to iterate over the values of a set and perform an action for each one. The each function is easy to use and keeps your code from being cluttered with many for loops.

var allAlts = new Array();
$('img').each(function(){
allAlts.push(this.alt);
});

These few lines of code will get the alt attribute of every image tag in your document and store it in an array.

This is useful because for some reason the :contains selector in jQuery is not case-insensitive. BTW the code below works with jQuery 1.3.

jQuery.expr[':'].contains = function(a,i,m){
  return jQuery(a).text().toUpperCase()
  .indexOf(m[3].toUpperCase())>=0;
};