参数为变量，可这样定义变量怎么不对呢
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>函数传参</title>
<script type="text/JavaScript">
function add(var x,var y,var z)
{
sum = x + y +z;
document.write(x+"、"+y+"、"+z+"和:"+sum+"<br/>");
}
add(1,2,3);
</script>
</head>
<body>
</body>
</html>
