javascript判断CheckBoxList必须选中一个
<asp:CheckBoxList   ID= "chkListPro "   runat= "server "   RepeatColumns= "2 "   Width= "282px "   Font-Size= "12px ">  
                                                                                                  </asp:CheckBoxList>  
 CheckBoxList数据源已绑定 
 是CheckBoxList,不要整一堆百度上的那些input,不好使
------解决方案--------------------这个好像得写在Button_Click中吧 
 chkListPro.Attribute.Add( "onclick ", "judge() ");
------解决方案--------------------function bool judge(){ 
 if(doucument.GetElementById( 'checkbox1 ').value== ' '&&doucument.GetElementById(checkbox2).value== ' ') 
 return false; 
 return true; 
 }
------解决方案--------------------弄半天没弄出来。。。。 
 帮顶,一起学吧
------解决方案--------------------可以用RequiredFieldValider控件,效果比js更好
------解决方案--------------------为什么要用JS啊,做循环,看CheckListBox的Item里是否有被选中的
------解决方案-------------------- <body MS_POSITIONING= "GridLayout ">   		 
 		 <form id= "Form1 " method= "post " runat= "server ">  
 		 <input type=checkbox id=111 value= '111 '>  
 		 <input type=checkbox id=222 value= '222 '>  
 		 <SCRIPT>  
 		function CheckSelect(frm) 
 			{ 
 				for(var i=0;i <frm.elements.length;i++) 
 				{ 
 					var e = frm.elements[i]; 
 					if(e.type ==  'checkbox ') 
 					{ 
 						if(e.checked) 
 						{	 
 							return; 
 						} 
 					} 
 				} 
 				alert( '至少选择一个 '); 
 			}  			 
  </SCRIPT>  
 		 <input type= "button " onclick= "CheckSelect(this.form) " value= "检查 ">  
 		 </form>  
 	 </body>
------解决方案--------------------学习
------解决方案-------------------- <script type= "text/javascript ">  
         function btnClick() 
         { 
             var list = document.getElementById( "chkList "); 
             var j = 0; 
             for(var i = 0 ; i  < list.rows.length;i++) 
             { 
                 var chk = list.rows[i].childNodes[0].childNodes[0]; 
                 if (chk.checked) 
                 { 
                     j++; 
                 } 
             } 
             return (j >  0); 
         } 
      </script>      
  <asp:Button ID= "btn " Text= "button " runat= "server "/>  
      <asp:CheckBoxList ID= "chkList " runat= "server ">  
          <asp:ListItem Text= "1 " Value= "1 ">  </asp:ListItem>  
          <asp:ListItem Text= "2 " Value= "2 ">  </asp:ListItem>  
          <asp:ListItem Text= "3 " Value= "3 ">  </asp:ListItem>  
          <asp:ListItem Text= "4 " Value= "4 ">  </asp:ListItem>  
      </asp:CheckBoxList>    
 protected void Page_Load(object sender, EventArgs e)