JAVASCRIPT

validate email input javascript onchange

 <script type="text/javascript">
 function ShowAlert() {
  var email = document.getElementById('txtEmailId');
  var filter = /^([a-zA-Z0-9_.-])+@(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/;
    if (!filter.test(email.value)) {
        alert('Please provide a valid email address');
        email.focus;
        return false;
    }
    else {
        alert("Thanks for your intrest in us, Now you 
        will be able to receive monthly updates from us.");
        document.getElementById('txtEmailId').value = "";
    }
 }
 </script> 

form validation for email in js

<script>  
function validateform(){  
var name=document.myform.name.value;  
var password=document.myform.password.value;  
  
if (name==null || name==""){  
  alert("Name can't be blank");  
  return false;  
}else if(password.length<6){  
  alert("Password must be at least 6 characters long.");  
  return false;  
  }  
}  

validate email input javascript onchange

   <input input type="text" name="txtEmailId" id="txtEmailId" /> 
   <input type="submit" class="button" value="Suscribe" name="Suscribe" 
            onclick="javascript:ShowAlert()" />