var trsID = Array('tr_email','tr_password','tr_password_repeat');
var inputsID = Array('email','password','password_repeat');

function initialize() {
	var isSet = false;
	for (var i=0; i<trsID.length; i++) {
		if (!isSet &&  document.getElementById(inputsID[i]).value=='') {
			document.getElementById(trsID[i]).className += ' setInput';
			document.getElementById(inputsID[i]).focus();
			isSet = true;
		}
	}
}

function change(index,element) {  			
	if (element.value=='') return;
		index=index+1;
		var isSet = false;
		
		for (var i=0; i<trsID.length; i++) {
			document.getElementById(trsID[i]).className = document.getElementById(trsID[i]).className.replace(/setInput/,'');
		}
		for (var i=index; i<trsID.length; i++) {				
			if ( document.getElementById(inputsID[i]).value=='') {
				document.getElementById(trsID[i]).className += ' setInput';						
				isSet = true;   						
				break; 		
		}  
	}

	if (!isSet) {
		for (var i = 0; i < trsID.length; i++) {
			if ( document.getElementById(inputsID[i]).value == '') {     				
				document.getElementById(trsID[i]).className += ' setInput';						
				break;   					
			}
		} 
	}
}