function initARC(formId,onClassRadio,offClassRadio,onClassCheckbox,offClassCheckbox) {
    var agt=navigator.userAgent.toLowerCase();

    // Browser Detection stuff
    this.major = parseInt(navigator.appVersion);
    this.ie     = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
    this.ie3    = (this.ie && (this.major < 4));
    this.ie4    = (this.ie && (this.major == 4) && (agt.indexOf("msie 4")!=-1) );
	this.iemac  = (this.ie && (agt.indexOf("mac")!=-1));

	if( !(this.iemac || ie3 || ie4) ){
		customiseInputs(formId,onClassRadio,offClassRadio,onClassCheckbox,offClassCheckbox);
	}
}




function addLabelProperties(f){
	if(typeof f.getElementsByTagName == 'undefined') return;
	var labels = f.getElementsByTagName("label"), label, elem, i = j = 0;
	
	while (label = labels[i++]){
		if(typeof label.htmlFor == 'undefined') return;
		elem = document.getElementById(label.htmlFor);
		//elem = f.elements[label.htmlFor]; /* old method */
		
		if(typeof elem == 'undefined'){
			//no label defined, find first sub-input
			var inputs = label.getElementsByTagName("input");
			if(inputs.length==0){
				continue;
			} else {
				elem=inputs[0];
			}
		} else if(typeof elem.label != 'undefined') { // label property already added
			continue;
		} else if(typeof elem.length != 'undefined' && elem.length > 1 && elem.nodeName != 'SELECT'){
			for(j=0; j<elem.length; j++){
				elem.item(j).label = label;
			}
		}
		elem.label = label;
	}
} 



/**
NAME: toggleLabelStyle()

ABOUT:
 This function is attached to our label's onClick event. So when the label is
 clicked this function alters the radio group's members to an unchecked state
 and style, and alters the currently selected label to the on style and checked
 state.

USAGE:
 ARC currently assumes that the label contains a FOR='id' in it's HTML. The other
 valid form of a label is <label>text <input /></label> - while it is possible
 to modify this code to allow for this form I have left this as an exercise for
 the reader.
 
PARAMS:
 formId   - Parent form of this label
 label    - The label for a radio button we wish to toggle
 onClass  - The CSS class name for the radio button's on style
 offClass - The CSS class name for the radio button's off style
*/
function toggleLabelStyle(formId, label, onClass, offClass){
	if(!document.getElementById || !label) return;
		
	var form = document.getElementById(formId); //label.form;
	if(!form) return;
	
	//find radio associated with label (if in htmlFor form)
	if(label.htmlFor) {
		var e = document.getElementById(label.htmlFor);
		
		if(e.type=="checkbox"){
			e.label.className = (e.label.className==onClass) ? offClass : onClass;
			e.checked = (e.label.className==onClass);
		} else if(e.type=="radio"){
			var radioGroup = form.elements[e.name];
			if(!radioGroup) return;
			
			for(var i=0; i<radioGroup.length; i++){
				if(radioGroup[i].label){
					radioGroup[i].label.className = ((radioGroup[i].checked=(radioGroup[i].id == e.id))
													 && radioGroup[i].label) ? onClass : offClass;
				}
			}
		}
	}
}



function customiseInputs(formId, onClassRadio, offClassRadio, onClassCheckbox, offClassCheckbox) {
	if(!document.getElementById) return;

	var prettyForm = document.getElementById(formId);
	if(!prettyForm) return;
		
	//onReset, reset radios to initial values
	prettyForm.onreset = function() { customiseInputs(formId, onClassRadio, offClassRadio, onClassCheckbox, offClassCheckbox); }
	
	//attach an easy to access .label reference to form elements
	addLabelProperties(prettyForm);

	var inputs = prettyForm.getElementsByTagName('input');
	for (var i=0; i < inputs.length; i++) {
		/* NB: Yeah, i know this code is duplicated - I can't figure out how to create a local, persistent
			variable within the anonymous function calls. Fix it if you can, and let me know. */
			
		//RADIO ONLY
		if( (inputs[i].type=="radio") && inputs[i].label && onClassRadio && offClassRadio){
			//hide element
			inputs[i].style.position="absolute"; inputs[i].style.left = "-1000px";
			//initialise element
			inputs[i].label.className=offClassRadio;
			//when the label is clicked, call toggleLabelStyle and toggle the label
			inputs[i].label.onclick = function (){ toggleLabelStyle(formId, this, onClassRadio, offClassRadio); return false; };
			//enable keyboard navigation
			inputs[i].onclick = function (){ toggleLabelStyle(formId, this.label, onClassRadio, offClassRadio); };
			//if the radio was checked by default, change this label's style to checked
			if(inputs[i].defaultChecked || inputs[i].checked){ toggleLabelStyle(formId, inputs[i].label, onClassRadio, offClassRadio); }
		}
		
		//CHECKBOX ONLY
		if( (inputs[i].type=="checkbox") && inputs[i].label && onClassCheckbox && offClassCheckbox){
			//hide element
			inputs[i].style.position="absolute"; inputs[i].style.left = "-1000px";
			//initialise element
			inputs[i].label.className=offClassCheckbox;
			inputs[i].checked = false;
			//when the label is clicked, call toggleLabelStyle and toggle the label
			inputs[i].label.onclick = function (){ toggleLabelStyle(formId, this, onClassCheckbox, offClassCheckbox); return false; };
			//enable keyboard navigation
			inputs[i].onclick = function (){ toggleLabelStyle(formId, this.label, onClassCheckbox, offClassCheckbox); };
			//if the radio was checked by default, change this label's style to checked
			if(inputs[i].defaultChecked || inputs[i].checked){ toggleLabelStyle(formId, inputs[i].label, onClassCheckbox, offClassCheckbox); }
		}

		if( (inputs[i].type=="checkbox") || (inputs[i].type=="radio") && inputs[i].label ){
			//Attach keyboard navigation
			if(!this.ie){ //IE has problems with this method
				//You could set these to grab a passed in class name if you wanted to
				//do something a bit more interesting for keyboard states. But for now the
				//generic dotted outline will do for most elements.
				inputs[i].label.style.margin = "1px";
				inputs[i].onfocus = function (){ this.label.style.border = "1px dotted #333"; this.label.style.margin="0px"; return false; };
				inputs[i].onblur  = function (){ this.label.style.border = "none"; this.label.style.margin="1px"; return false; };
			}
		}
}
}