Ajax带提示的验证表单实例

!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
html xmlns="http://www.w3.org/1999/xhtml">
head>
meta http-equiv="content-type" content="text/html; charset=utf-8" />
title>带提示的Ajax验证表单/title>
style type="text/css">
form {
  width:500px;
  border:1px solid #ccc;
}
fieldset {
  border:0;
  padding:10px;
  margin:10px;
  position:relative;
}
label {
  display:block;
  font:normal 12px/17px verdana;
}
input {width:160px;}
span.hint {
  font:normal 11px/14px verdana;
  background:#eee url(images/bg-span-hint-gray.gif) no-repeat top left;
  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 url(images/bg-span-hint-welldone.jpg) no-repeat top left;
  border-color:#749e5c;
  color:#000;
}
fieldset.kindagood span.hint {
  background:#ffffcc url(images/bg-span-hint-kindagood.jpg) no-repeat top left;
  border-color:#cc9933;
}
fieldset.welldone {
  background:transparent url(images/bg-fieldset-welldone.gif) no-repeat 194px 19px;
}
fieldset.kindagood {
  background:transparent url(images/bg-fieldset-kindagood.gif) no-repeat 194px 19px;
}
/style>
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; iinputs.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>
/head>
body>
form
  action="#"
  name="basicform"
  id="basicform" >
fieldset>
  label for="username">用户名:/label>
  input
    type="text"
    id="username"
    onkeyup="checkUsernameForLength(this);" />
  span class="hint">用户名最低6位哦/span>
/fieldset>
fieldset>
  label for="password">密码:/label>
  input
    type="password"
    id="password"
    onkeyup="checkPassword(this);" />
  span class="hint">密码需要4到8位哦/span>
/fieldset>
fieldset>
  label for="email">Email地址:/label>
  input
    type="text"
    id="email"
    onkeyup="checkEmail(this);" />
  span class="hint">You can enter your real address without worry - we don't spam!/span>
/fieldset>
/form>
/body>
/html>