var usernameCheckerTimer; function usernameChecker() {
    var username = document.getElementById("ctl00_ContentPlaceHolder1_txtLogin").value; var spanAvailability = document.getElementById("ctl00_ContentPlaceHolder1_spanAvailability"); clearTimeout(usernameCheckerTimer); if (username.length == 0)
        spanAvailability.innerHTML = ""; else { spanAvailability.innerHTML = "<span style='color: #ccc;'>checking...</span>"; usernameCheckerTimer = setTimeout("checkUsernameUsage('" + username + "');", 750); } 
}
function checkUsernameUsage(username) { PageMethods.IsUserAvailable(username, OnSucceeded); }
function OnSucceeded(result, userContext, methodName) {
    var spanAvailability = document.getElementById("ctl00_ContentPlaceHolder1_spanAvailability"); if (methodName == "IsUserAvailable") {
        if (result == true)
            spanAvailability.innerHTML = "<span style='color: DarkGreen;'>Available</span>"; else
            spanAvailability.innerHTML = "<span style='color: Red;'>Unavailable</span>";
    } 
}