Hi AhmadCh,
Refer the below article.
Also i have created a sample which fullfill your requirement
HTML
<div>
<input type="text" name="name" id="txtName" />
<input type="button" value="Submit" id="btnSubmit" name="Submit" />
</div>
<div>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
$(function () {
$('[id*=btnSubmit]').click(function () {
var regex = /^[A-Za-z ]+$/;
if (!regex.test($('[id*=txtName]').val())) {
alert('Please Enter Only Alphabets');
$('[id*=txtName]').val('');
}
});
});
</script>
</div>
Demo