window.onerror不会死循环

<script>
(function(){
    window.onerror = function(msg,url,line){
        var c = {};
        if(!window.onerror.xxx){
            try{
                version = c.c.c;//出错，会不会触发window.onerror?调试证明，不会循环触发
            }catch(e){
                window.onerror.xxx = true;//防止死循环
            }
        }
        return true;
    }
})();
var a = {};
a.b.c
</script>