function trim(stringa){
		regExp = /^\s$/;
		return stringa.replace(regExp,"");
	}
	
	var regExp_password = /^[a-zA-Z0-9]{6,25}$/;
	var regExp_email = /^[\w\.\-]+\@[\w\.\-]+\.+[\w]+$/;
	
	/* Evaluate Regular Expression */
	function check_regExp(regExp,field_x){
	    if (field_x.value != ''){
    		if (!regExp.test(field_x.value)){                                
    		    return false;
    		}
    		
    		return true;
    	}
	}			
	
	/* Seleziona tutte le checkbox del form */
	function selectAll(obj,parentForm){						
		
		lista_check = parentForm.elements;
						
		for (i = 0; i < lista_check.length; i++){
			if(lista_check.item(i).type == 'checkbox'){
		
				lista_check.item(i).checked = obj.checked;
			}
		}
		
	}
	
	function show_stain(stain,img_folder){		
		document.getElementById(stain).src = img_folder+'/macchia.gif';
	}
	
	function hide_stain(stain,img_folder){
		document.getElementById(stain).src = img_folder+'/pix.gif';
	}