function dynamicSelect(id1, id2) {
	// Feature test to see if there is enough W3C DOM support
	if (document.getElementById && document.getElementsByTagName) {
		// Obtain references to both select boxes
		var sel1 = document.getElementById(id1);
		var sel2 = document.getElementById(id2);
		// Clone the dynamic select box
		var clone = sel2.cloneNode(true);
		
		// FIX FOR IE: IE resets the selected property when cloning...
		clone.selectedIndex = sel2.selectedIndex;
		
		// Obtain references to all cloned options 
		var clonedOptions = clone.getElementsByTagName("option");
		
		
		// Onload init: call a generic function to display the related options in the dynamic select box
		refreshDynamicSelectOptions(sel1, sel2, clonedOptions);
		// Onchange of the main select box: call a generic function to display the related options in the dynamic select box
		sel1.onchange = function() {
			refreshDynamicSelectOptions(sel1, sel2, clonedOptions);
		};
	}
}
function refreshDynamicSelectOptions(sel1, sel2, clonedOptions) {
	
	while (sel2.options.length) {
		sel2.remove(0);
	}
	// Create regular expression objects for "select" and the value of the selected option of the main select box as class names
	var pattern1 = /( |^)(select)( |$)/;
	var pattern2 = new RegExp("( |^)(" + sel1.options[sel1.selectedIndex].value + ")( |$)");
	// Iterate through all cloned options
	for (var i = 0; i < clonedOptions.length; i++) {
		// If the classname of a cloned option either equals "select" or equals the value of the selected option of the main select box
		if (clonedOptions[i].className.match(pattern1) || clonedOptions[i].className.match(pattern2)) {
			
			// Clone the option from the hidden option pool and append it to the dynamic select box
			
			// FIX FOR IE: IE resets the selected property when cloning...
			
			var clone = clonedOptions[i].cloneNode(true);
			clone.selected=clonedOptions[i].selected;
			
			sel2.appendChild(clone);
			
		}
	}
	
}