我正在尝试在javascript中调用耗时函数之前向用户加载“正在加载”消息。HTML:Foo​Javascript:varfoo=document.getElementById('foo');functiontellViewerLoading(){//Telltheuserthatloadingisoccuring.foo.innerHTML='loading...';}functionsomeActionThatTakesALongTime(){//Dosomeactionthattakesalongtime.vari=0;while(iJSFiddle:http://jsfidd