extjs touch ajax 交互，遮罩，提示

tiger_request_num = 0;

Ext.override(Ext.data.Connection,{
    request: Ext.Function.createSequence(Ext.data.Connection.prototype.request,function () {
        if (tiger_request_num == 0) {

            Ext.Viewport.add({xtype:'loadmask',message:'正在努力与后台交互...',id:'tigerleq-panel-mask'  //赋给它id  
            }); 

        }
        tiger_request_num++;
    }),onUploadComplete: Ext.Function.createSequence(Ext.data.Connection.prototype.onUploadComplete,function () {

        tiger_request_num--;
        if (tiger_request_num == 0) {
            Ext.Viewport.remove(Ext.getCmp('panel-mask'));
        }
    }),onComplete: Ext.Function.createSequence(Ext.data.Connection.prototype.onComplete,function () {

        tiger_request_num--;
        if (tiger_request_num == 0) {
            Ext.Viewport.remove(Ext.getCmp('tigerleq-panel-mask'));
        }
    })
});