Hi, i insert: true false; , now it's working
<script type="text/javascript">
$(document).ready(function () {
$("#Submit1").click(function () {
$.ajax({
contentType: "text/html; charset=utf-8",
data: {ID: $('#Text1').val(),
ID2: $('#Text2').val()
},
url: "fetchcustomer.aspx",
dataType: "html",
success: function (data) {
$("#CustomerDetails").html(data);
}
});
<big>return false;</big>
});
</script>