var B_IE = (document.all) ? true : false;
var B_DOM = (document.getElementById) ? true : false;

var currentImage="";
	
function chgElem(elem) {
	if (!currentImage=="") {
		setStyle(currentImage,"none");
	}
	setStyle(elem,"block");
	currentImage = elem;
}
	
function setStyle(ele,styleStr) {
	eval("document."+(B_IE ? "all." : (B_DOM ? "getElementById('" : ""))+ele+(B_DOM && !B_IE ? "')" : "")+(B_DOM || B_IE ? ".style" : "")+".display='"+styleStr+"'");
}