here is a simple program will guide how to do client side validation of Form in JavaScript.
Name : <asp:TextBox ID="txtName" /> Email : <asp:TextBox ID="txtEmail" /> Web URL : <asp:TextBox ID="txtWebUrl" /> Zip : <asp:TextBox ID="txtZip" /> <asp:Button ID="btnSubmit" OnClientClick=" return validate()" runat="server" Text="Submit" /> Now on the source code of this form in script tag write the following code: <script language="javascript" type="text/javascript"> function validate() { if (document.getElementById("<%=txtName.ClientID%>").value=="") { alert("Name Feild can not be blank"); document.getElementById("<%=txtName.ClientID%>").focus(); return false; } if(document.getElementById("<%=txtEmail.ClientID %>").value=="") { alert("Email id can not be blank"); document.getElementById("<%=txtEmail.ClientID %>").focus(); return false; } var emailPat = /^(\".*\"|[A-Za-z]\w*)@(\[\d{1,3}(\.\d{1,3}){3}]|[A-Za-z]\w*(\.[A-Za-z]\w*)+)$/; var emailid=document.getElementById("<%=txtEmail.ClientID %>").value; var matchArray = emailid.match(emailPat); if (matchArray == null) { alert("Your email address seems incorrect. Please try again."); document.getElementById("<%=txtEmail.ClientID %>").focus(); return false; } if(document.getElementById("<%=txtWebURL.ClientID %>").value=="") { alert("Web URL can not be blank"); document.getElementById("<%=txtWebURL.ClientID %>").value="http://" document.getElementById("<%=txtWebURL.ClientID %>").focus(); return false; } var Url="^[A-Za-z]+://[A-Za-z0-9-_]+\\.[A-Za-z0-9-_%&\?\/.=]+$" var tempURL=document.getElementById("<%=txtWebURL.ClientID%>").value; var matchURL=tempURL.match(Url); if(matchURL==null) { alert("Web URL does not look valid"); document.getElementById("<%=txtWebURL.ClientID %>").focus(); return false; } if (document.getElementById("<%=txtZIP.ClientID%>").value=="") { alert("Zip Code is not valid"); document.getElementById("<%=txtZIP.ClientID%>").focus(); return false; } var digits="0123456789"; var temp; for (var i=0;i<document.getElementById("<%=txtZIP.ClientID %>").value.length;i++) { temp=document.getElementById("<%=txtZIP.ClientID%>").value.substring(i,i+1); if (digits.indexOf(temp)==-1) { alert("Please enter correct zip code"); document.getElementById("<%=txtZIP.ClientID%>").focus(); return false; } } return true; } </script> And in code behind file just write the below code. Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load btnSubmit.Attributes.Add("onclick", "return validate()") End Sub
Now you will get a form with proper validation.
I hope this is going to help you