ASP.Net: Text Box Validation - Part II

ASP.Net: Text Box Validation Part I

Introduction

In this article, I explain some more validations of Text box control in ASP.Net.

Requirement

Add the following line in the head section to create a function for validation.

<script language="javascript" type="text/javascript">

Then create a function:

 

function validate()
{
. //function body
.
.
return true;
}

 

Solution

1. Text box cannot be blank :
   
   This kind of validation does not allow blank text box controls in ASP.Net. Add the following function body:

    

   if (document.getElementById("<%=txtName.ClientID%>").value=="")
   {
        alert("Name Feild can not be blank");
        document.getElementById("<%=txtName.ClientID%>").focus();
        returnfalse;
   }

   Where txtName is the Id of a Text Box control. 

2. Email id Validation
   
   This kind of validation accepts only email id syntax in a text box control in ASP.Net. Add the following function body:

    

   if(document.getElementById("<%=txtEmail.ClientID %>").value=="")
   {
   alert("Email id can not be blank");
   document.getElementById("<%=txtEmail.ClientID %>").focus();
   returnfalse;
   }
   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();
   returnfalse;
   }

   Where txtEmail is the Id of a Text Box.

3. Web URL

   This kind of validation only accepts a web URL in a Text box control. Add the following function body:
   

   if(document.getElementById("<%=txtWebURL.ClientID %>").value=="")
   {
               alert("Web URL can not be blank");
               document.getElementById("<%=txtWebURL.ClientID %>").value="http://"
               document.getElementById("<%=txtWebURL.ClientID %>").focus();
               returnfalse;
    }
    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();
             returnfalse;
     }

   Where txtWebURL is the Id of a Text Box.
   

4. ZIP Format

   This kind of validation only accepts a ZIP format of data in the Text Box control in ASP.Net. Add the following function body:

    

   if (document.getElementById("<%=txtZIP.ClientID%>").value=="")
   {
   alert("Zip Code is not valid");
   document.getElementById("<%=txtZIP.ClientID%>").focus();
   returnfalse;
   }
   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();
   returnfalse;
   }
   }

   Where txtZIP is the Id of a text box.

   When you done with all call the function validate on the Button on which you want output as in the following :
   

   <asp:Button ID="btnSubmit" OnClientClick=" return validate()" runat="server" Text="Submit" />

Now save the entire work and view the page in a browser. It will work perfectly.