按需加载UI

fuction showHelp() { var request = new Sys.Net.WebRequest(); request.set_httpVerb("GET"); request.set_url('help.aspx'); request.add_completed(fuction(executor) { if (executor.get_responseAvailable()) { var helpDiv = $get('HelpDiv'); var helpLink = $get('HelpLink'); var helpLinkBounds = Sys.UI.DomElement.getBounds(helpLink); helpDiv.style.top = (helpLinkBounds.y+helpLinkBounds.height)+"px"; var content = executor.get_responseData(); helpDiv.innerHtml = content; helpDiv.style.display = "block"; } }); var executor = new Sys.Net.XMLHttpExecutor(); request.set_executor(executor); executor.executeRequest(); }

摘自 asp.net 3.5 构建web 2.0 门户站点，P245

需引用asp.net ajax 的库