// mouseover botão submit
function buttons() {
	var objs = document.getElementsByTagName("input");
	for (var b=0, obj; obj=objs[b]; b++) {
		if (obj.type == "image") {
			obj.onmouseover = function() {
				var img = this.src;
				var len = img.length;
				var imgtype = img.substring(len-3, len);
				var hover = img.substring(0, len-4) + "-hover." + imgtype;
				this.src = hover;
			}
			obj.onmouseout = function() {
				var img = this.src.replace("-hover", "");
				this.src = img;
			}
		}
	}
}

window.onload = function() { if (document.getElementById) {
	// inicializa eventos
	buttons();
}}