YouuseMicrosoft.NETframeworkv3.5tocreateaMicrosoftASP.NETapplicationforCertkiller.com.
Thecodesegmentbelowiswrittentocreateaclient-script
ThisnewlycreatedscriptwillmakeuseofASP.NETAJAX.ThescriptwillalsoupdatethetextofalltheLabelcontrolsinthewebform.IthascometoyourattentionthattheLabelcontrolsarenotupdatedwhentheclientscriptfunctionistested.However，youreceivethe"’null’isnullornotanobject"Javascripterrormessageinthebrowser.
Whatshouldyoudo？（）
正确答案：参考C
