// Creating custom :external selector
$.expr[':'].external = function(obj){
    return !obj.href.match(/^mailto\:/)
            && (obj.hostname != location.hostname);
};

$(document).ready(function(){
	// Add 'external' CSS class to all external links
	$("a[href^='/external.php']").colorbox({
		width:"500px", 
		height:"300px"
	});
});