<script type="text/javascript">

function checkUsernameForLength(whatYouTyped) {
    var fieldset = whatYouTyped.parentNode;
    var txt = whatYouTyped.value;
    if (txt.length > 5) {
        fieldset.className = "welldone";
    }
    else {
        fieldset.className = "";
    }
}





function checkPassword(whatYouTyped) {
    var fieldset = whatYouTyped.parentNode;
    var txt = whatYouTyped.value;
    if (txt.length > 3 && txt.length < 8) {
        fieldset.className = "kindagood";
    } else if (txt.length > 7) {
        fieldset.className = "welldone";
    } else {
        fieldset.className = "";
    }
}

function checkEmail(whatYouTyped) {
    var fieldset = whatYouTyped.parentNode;
    var txt = whatYouTyped.value;
    if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(txt)) {
        fieldset.className = "welldone";
    } else {
        fieldset.className = "";
    }
}



function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}


function prepareInputsForHints() {
  var inputs = document.getElementsByTagName("input");
  for (var i=0; i<inputs.length; i++){
    inputs[i].onfocus = function () {
      this.parentNode.getElementsByTagName("span")[0].style.display = "inline";
    }
    inputs[i].onblur = function () {
      this.parentNode.getElementsByTagName("span")[0].style.display = "none";
    }
  }
}
addLoadEvent(prepareInputsForHints);

</script>

<fieldset>Имя:<br>
<input type="text" name="name" onkeyup="checkUsernameForLength(this);" id='name'>
<span class="hint">Введите ваше имя!</span><br></fieldset>

<fieldset>Пароль:<br>
<input type="password" onkeyup="checkPassword(this);" name="password1">
<span class="hint">Введите пароль, не меньше 6 знаков.</span><br></fieldset>

<fieldset>Повторите пароль:<br>
<input type="password" onkeyup="checkPassword(this);" name="password2">
<span class="hint">Повторите пароль.</span><br></fieldset>

<fieldset>Ваш E-Mail:<br>
<input type="text" onkeyup="checkEmail(this);" name="email">
<span class="hint">Введите E-mail, просим вас указывать реальные адреса.</span><br></fieldset>

fieldset {
    border:0;
    padding:10px;
    margin:10px;
    position:relative;
}
span.hint {
    font:normal 11px/14px verdana;
    background:#eee;
    color:#444;
    border:1px solid #888;
    padding:5px 5px 5px 40px;
    width:250px;
    position:absolute;
    margin: -12px 0 0 14px;
    display:none;
}


fieldset.welldone span.hint {
    background:#9fd680;
    border-color:#749e5c;
    color:#000;
}
fieldset.kindagood span.hint {
    background:#ffffcc;
    border-color:#cc9933;
}