<script src=”https://code.jquery.com/jquery-1.11.3.js”></script>
<script >
function ValidateEmail(emailId) {
var expr = /^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
return expr.test(emailId);
};

$(document).ready(function(){
$(“#submit “).click(function(){

var email = $(“#email”).val();

if(email == ”){
alert(“Please enter Email Id”);
}
else if (!ValidateEmail(email)) {
alert(“Invalid email address”);
}

else {
alert(“Valid Email id”);
}
})
});
</script>

<input id=”email” type=”text” />
<input id=”submit” type=”button” value=”Validate” />