停止while循环

winform.button.oncommand = function(id,event){
        if(winform.button.text == "开始"){
                winform.button.text = "停止"
                myfunc()
       }
        else winfom.button.text = "开始"               
}
myfunc = function(){
        while(win.delay(1)){
                if(winform.button.text == "开始")
                break;
        }         
}