var imgOk = new Image();  imgOk.src  = 'images/icon-good.gif';
var imgNok = new Image(); imgNok.src = 'images/icon-not-good.gif';
var imgReq = new Image(); imgReq.src = 'images/blank.gif';
var iconId = 'status';
var msgId = 'msg';
var uid = 0;

function username_init(userId){
    uid = userId;            
}
    
function username_check(txt){
    if(txt.value==''){
        document.getElementById(iconId).src = imgReq.src;
        document.getElementById(msgId).innerHTML=' ';
    } else {
        var p = 'username=' + encodeURIComponent(txt.value) + '&userid=' + uid;
        var req = new Ajax.Request( "/username_api.php", { method:'get', parameters:p, onComplete:username_updateDisplay} );    
    }
}
    
function username_updateDisplay(req){
    try{
        var tall = req.responseText.split('|');
        var img = document.getElementById(iconId);
		var message = tall[1];
        switch(tall[0]){
            case 'ok'   :
				{
					img.src='images/icon-good.gif';
					document.getElementById(msgId).className = 'note';
					break;
				}
            case 'nok'  :
				{
					img.src='images/icon-not-good.gif';
					if ( tall[1]=='error checking' )
					{
						document.getElementById(msgId).className = 'not_ok';
						message = 'Please use only alpha-numeric characters.';
					}
					else
					{
						document.getElementById(msgId).className = 'not_ok';
					}
					break;
				}
            default    : img.src='images/blank.gif'; break;
        }
        document.getElementById(msgId).innerHTML = message+' '; 
    } catch (e) {
    }
}