function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}
// Begin popup window function.
function popUps() {

	if (!document.getElementsByTagName) return false;
	
	var links = document.getElementsByTagName("a");
	
	for (var i=0; i<links.length; i++) {
	
		if (links[i].getAttribute("class") == "popup-small") {
			links[i].onclick = function() {
				popUpSmall(this.getAttribute("href"));
				return false;
			}  
		}
		else if (links[i].getAttribute("class") == "popup-medium") {
			
		//else if (links[i].className.indexOf("popup-medium)){	
			links[i].onclick = function() {
				popUpMedium(this.getAttribute("href"));
				return false;
			}
		}
		
		else if (links[i].getAttribute("class") == "popup-large") {
			links[i].onclick = function() {
				popUpBig(this.getAttribute("href"));
				return false;
			}
		}
	}
}

// uses class attribute of link to determine size of popup.

function popUpSmall(winURL) {
  window.open(winURL,"popup-small","width=500,height=480");
}

function popUpMedium(winURL) {
	window.open(winURL,"popup-medium","width=650,height=550,location=yes,scrollbars=yes,menubar=yes,toolbar=yes,resizable=yes");
}

function popUpBig(winURL) {
	window.open(winURL,"popup-large","width=800,height=600");
}

addLoadEvent(popUps);