var selected=0;
function selectAll(frmName) {
	var objRef = document.getElementById(frmName);
	if (objRef == null) {
		alert('对象引用错误！');
	}
	if(selected==1){
		selected=0;
	}else{
		selected=1;
	}
	var child=objRef.elements;
    var len=child.length;
	for (i = 0; i < len; i++) {
		if(child[i].type=='checkbox'){
			if(selected==1){
				child[i].checked = true;
			}else{
				child[i].checked = false;
			}
		}
	}
}
function addLoadEvent(func) { 
  var oldonload = window.onload; 
  if (typeof window.onload != 'function') { 
    window.onload = func; 
  } else { 
    window.onload = function() { 
      if (oldonload) { 
        oldonload(); 
      } 
      func(); 
    } 
  } 
}