让easyui 的alert 消息框中的确定按钮支持空格键

var _messager = $.extend({},$.messager);
$.extend($.messager,{
    alert:function(title, msg, icon, fn){
        var win = _messager.alert.call(this,title,msg,icon,fn);

        win.on('keyup',function(e){
            if(e.which ==32){
                win.window('close');
                if (fn){
                    fn();
                    return false;
                }
            }
        });

    },
    confirm: function(title,msg,fn){
        var win = _messager.confirm.call(this,title,msg,fn);
        win.on('keyup',function(e){
            if(e.which ==32 || e.which ==13){
                win.window('close');
                if (fn){
                    fn(true);
                    return false;
                }
            }

            if(e.which == 27) { // esc
                win.window('close');
                if(fn){
                    fn(false);return false;
                }
            }
        });
    },
    prompt:function(title,msg,fn){
        var win = _messager.prompt.call(this,title,msg,fn);
        win.on('keyup',function(e){
            if(e.which ==13){
                win.window('close');
                if (fn){
                    fn($('.messager-input', win).val());
                    return false;
                }
            }

            if(e.which == 27) { // esc
                win.window('close');
                if(fn){
                    fn();return false;
                }
            }
        });
    }
});