本文实例讲述了Ajax带提示的验证表单。分享给大家供大家参考。具体如下：
这是一个常用的Ajax表单验证程序，实时提示你输入的字符是否符合要求，简洁明快，便于修改，这是用JavaScript实现的，没有掺杂其它的框架类代码，因此比较实用。
运行效果截图如下：
在线演示地址如下：
http://demo.jb51.net/js/2015/js-ajax-table-check-codes/
具体代码如下：
<!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; 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> </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>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>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>You can enter your real address without worry - we don't spam!</span> </fieldset> </form> </body> </html>
希望本文所述对大家的javascript程序设计有所帮助。