You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. 
You create a Web form by using ASP.NET AJAX. 
You write the following client-script code fragment to handle the exceptions thrown from asynchronous 
postbacks. （Line numbers are included for reference only.） 
01 <script type="text/javascript"> 02 function pageLoad（） 
03 { 
04 var pageMgr = 
05 Sys.WebForms.PageRequestManager.getInstance（）； 
06 
07 } 
08 
09 function errorHandler（sender， args） 
10 { 
11 
12 } 
| English | Chinese | Japan | Korean | - 146 - Test Information Co.， Ltd. All rights reserved. 13 </script> 
You need to ensure that the application performs the following tasks： &iexcl；¤Use a common clien-script function named errorHandler. &iexcl；¤Update a Label control that has an ID named lblEror with the error message. &iexcl；¤Prevent the browser from displaying any message box or Javascript error 
What should you do？ （）

You create a Microsoft ASP.NET application by using the Microsoft .NET Framework version 3.5. 
You write the following code segment to create a client-script function. （Line numbers are included for reference only.） 
01 function updateLabelControl（labelId， newText） { 
02 var label = $find（labelId）； 
03 label.innerHTML = newText； 
04 } 
The client script function uses ASP.NET AJAX and updates the text of any Label control in the Web form. 
When you test the client script function， you discover that the Label controls are not updated. Youreceive 
| English | Chinese | Japan | Korean | - 145 - Test Information Co.， Ltd. All rights reserved. the following JavaScript error message in the browser： "’null’ is null or not an object." You need to resolve the error. 
What should you do？（）