function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {  // if window.onload has already happened
		window.onload = func;
	} else { // if it's our FIRST function (window not yet loaded)
		window.onload = function() {
			oldonload();
			func();
		}
	}
}


function swapimage(image_id,state) {
	//alert('development note 1');
	if (!document.getElementsByTagName) return false; // DOM compatability check
	var images = document.getElementById(image_id);
	
	switch(image_id){
		case "searchbut_land":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_land_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_land.gif");
			}
			break;
			
		case "searchbut_landb":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_landb_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_landb.gif");
			}
			break;
			
					
		case "searchbut_homes":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_newhomes_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_newhomes.gif");
			}
			break;
			
		case "searchbut_homesb":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_newhomesb_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_newhomesb.gif");
			}
			break;
			
		case "searchbut_resinv":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_resinv_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_resinv.gif");
			}
			break;
		
		case "searchbut_reslet":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_reslet_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_reslet.gif");
			}
			break;
		
			
		case "searchbut_resinvb":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_resinvb_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_resinvb.gif");
			}
			break;
			
		case "searchbut_comm":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_commercial_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_commercial.gif");
			}
			break;
			
		case "searchbut_commb":
			if(state == 'over'){
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_commercialb_over.gif");
			} else {
				images.setAttribute("src", "http://www.dps-group.co.uk/btns/submit_commercialb.gif");
			}
			break;
			
		default:
			break;
	}
}

addLoadEvent("swapimage");