// enables the register button if the user agrees to the TOS
function EnableRegister(agreed)
{
    $('SaveButton').disabled = !agreed;
}
// username ajax call to see if the username already exists in the db
function UsernameExists(username)
{
    var url = 'ajax.aspx';
    var parms = 'method=IsDuplicateUsername&username='+username;
    var myAjax = new Ajax.Request(url, {method: 'get', parameters: parms, onSuccess: GetUsernameExists, onFailure: UsernameFailure} );
    
}
// if the server call succeeds
function GetUsernameExists(request)
{
    if(request.responseText=='true')
        alert('Username already exists.\nPlease choose another.');
}
// if the server call fails
function UsernameFailure(request)
{
    alert(request.statusText);
}