请前辈们给这个方法几句话让这个全选的方法不选择disabled的选择框

Question

bindCheckAll: function(str) {
var a = document.getElementsByName(str);
var n = a.length;
for (var i = 0; i < n; i++)
a[i].checked = window.event.srcElement.checked;
},

Answer 1

 a[i].checked = window.event.srcElement.checked;
->
if (!a[i].disabled=='disabled') a[i].checked = window.event.srcElement.checked;