如何判断同名复选框是否有被选中,
 问题1 
 我用了一组同名的复选框,当复选框一个也没有被选中时,弹出警告框 
  <script   language= "javascript ">  
 function   submitchecken()   { 
 if   (document.checkdomain.Cp_DnsName.value   ==    " ")   { 
 alert( "请至少选择一个域名后缀 "); 
 document.checkdomain.Cp_DnsName.focus(); 
 return   false; 
 } 
 return   true; 
 } 
  </script>  
  <form   method= "post "   action= "ke.asp "   name= "checkdomain "   onsubmit=    "return   submitchecken(); ">  
                    <table   width= "180 "   border= "0 "   cellpadding= "0 "   cellspacing= "0 ">  
                                <tr>  
                                      <td   align= "left ">  <input   name= "Cp_DnsName "   type= "checkbox "   value= ".com "   checked= "checked "   />  </td>  
                                      <td   align= "left "> .com </td>  
                                      <td   align= "left ">  <input   name= "Cp_DnsName "   type= "checkbox "   value= ".net "   />  </td>  
                                      <td   align= "left "> .net </td>  
                                      <td   align= "left ">  <input   name= "Cp_DnsName "   type= "checkbox "   value= ".org "   />  </td>  
                                      <td   align= "left "> .org </td>  
                                </tr>  
                                <tr>  <td>  <input   type= "submit "   name= "Submit "   value= "查询 ">  </td>  </tr>  
     </table>  
  </form>    
 问题2 
 因本人分数数不够,只好多问个问题(希望大家不要打我) 
 怎样判断字符是否都为简体中文
------解决方案--------------------question 1:   
  <!DOCTYPE HTML PUBLIC  "-//W3C//DTD HTML 4.0 Transitional//EN ">  
  <HTML>  
  <HEAD>  
  <TITLE>  New Document  </TITLE>  
  <META NAME= "Generator " CONTENT= "EditPlus ">  
  <META NAME= "Author " CONTENT= " ">  
  <META NAME= "Keywords " CONTENT= " ">  
  <META NAME= "Description " CONTENT= " ">  
  </HEAD>    
  <BODY>  
  <script language= "javascript ">  
 function submitchecken() { 
 	for(var i=0;i <document.checkdomain.Cp_DnsName.length;i++){ 
 		if (document.checkdomain.Cp_DnsName[i].checked) { 
 			return true; 
 		} 
 	}  	 
 	alert( "请至少选择一个域名后缀 "); 
 	//document.checkdomain.Cp_DnsName.focus();  不支持focus的 
 	return false; 
 } 
  </script>  
  <form method= "post " action= "ke.asp " name= "