function erase( el ) {
	el.value = '';
}
function verif_input() {
    var el = document.getElementById('input');
    if(el) {
       var txt = el.value;
       txt.replace(/^s+|s+$/g, '') ;
       if( '' == txt ) {
          alert('Oops!');
          el.focus();
          return false;
      }
    }
return true;
}
function verif_email( el ) {
	var email = el.value;
	var verif = /^[a-zA-Z0-9_-]+@[a-zA-Z0-9-]{2,}[.][a-zA-Z]{2,3}$/
	if (verif.exec(email) == null)
	{
		alert("??? "+email+" ???");
		el.focus();
		return false;
	} else {
		return (verif_input());
	}	
}

//		getElementsByClassName
document.getElementsByClassName = function( needle ) {
  var my_array = document.getElementsByTagName( '*' );
  var retvalue = new Array();
  var i;
  var j;

  for( i = 0,j = 0; i < my_array.length; i++ )   {
    var c = " " + my_array[i].className +' ';
    if( c.indexOf( ' ' +needle + ' ' ) != -1 ) {
      retvalue[j++] = my_array[i];
    }
  }
  return retvalue;
}