Want to disabled asp:LinkButton by javascript function

Question

I have a textbox and a linkbutton, i want that if textbox is empty then linkbutton disabled otherwise linkbutton enabled.

 

code are :

 

<input runat="server" type="text" id="txtName" onblur="CheckName('txtName','LinkButton1')" />

 

 <asp:LinkButton Enabled="false" ID="LinkButton1" runat="server" OnClick="LinkButton1_Click">LinkButton</asp:LinkButton>

 

 

and javascript function are :

 

 function CheckName(txt,btn)

{

var Name1= document.getElementById(txt).value; 

if(Name1 != null)

{

 document.getElementById(btn).disabled = false;

}

else

document.getElementById(btnNext).disabled = true; 

}

 

 Please help.

Thanks in advance.