I had a situation where I wanted a loading icon to appear when the user clicked submit in an ASP.NET form and the button to be hidden. However I didn't want the image to display if the form failed the client side validation.
The solution is to call the Page_ClientValidate method that ASP.NET uses. It takes one parameter which is the name of the validation group the button belongs to.
$(function(){
var button = $("#<%=button.ClientID%>");
var loadingImage = $("#loadingImage");
button.click(function(){
if(Page_ClientValidate("")){
button.css("display","none");
loadingImage.css("display","block");
}
});
});