Refresh Grid

var isrefresh = false;
function RefrshGrid() {
if (isrefresh)
document.getElementById('<%=btnrefresh.ClientID%>').click();

}

--on Close Call this function
if (typeof (window.parent.RefrshGrid) != 'undefined') {
window.parent.RefrshGrid();
}

Using JavaScript and UpdatePanels ,read,write xml

http://www.ajaxtutorials.com/ajax-tutorials/using-javascript-and-updatepanels-in-asp-net-3-5/

client side validation

Client Side Validation with JavaScript in ASP.

http://www.dotnetheaven.com/UploadFile/purankaushal/103292006010736AM/1.aspx