jquery ajax显示对号和错号，用于验证输入验证码是否正确

<script src="js/j.js"></script>

<script>

$(document).ready(function(e) {

$('#yes').hide();

$('#no').hide();

$('input[name=gcode]').keyup(function(){

if($(this).val().length==4){

$.post('gbook.php',{cc:$('input[name=gcode]').val()},function(msg){

	if(msg=='yes'){

	$('#no').hide();

		$('#yes').show();

}else{

	$('#yes').hide();

		$("#no").show();

}

});

}

});

});

</script>

.sl-error-verifycode {

background-image: url("images/icons.png");

background-position: -26px 0;

background-repeat: no-repeat;

display: block;

font-size: 18px;

height: 23px;

line-height: 20px;

margin-left: 180px;

margin-top: -25px;

position: relative;

text-align: center;

width: 20px;

z-index: 2;

}

.sl-correct-verifycode {

background-image: url("images/icons.png");

background-position: -50px 0;

background-repeat: no-repeat;

display: block;

font-size: 18px;

height: 23px;

line-height: 20px;

margin-left: 180px;

margin-top: -25px;

position: relative;

text-align: center;

width: 20px;

z-index: 2;

}

<tr>

<td height="40" align="right">验证码：</td>

<td height="40"><span class="addred">*</span></td>

<td height="40">

<input type="text" name="gcode" id="textfield7" class="txtlist">

<span id="yes" class="sl-correct-verifycode"></span><span id="no" class="sl-error-verifycode"></span>

<img style="float:right; margin-top:-25px; margin-right:300px;" align="middle" src="inc/cc.php" onClick="this.src='inc/cc.php?'+new Date" title="点击换一张图片" width="100px"></td>

</tr>

<?php

session_start();

if(isset($_POST['cc'])){

$cc = strtolower($_POST['cc']);

$ss = strtolower($_SESSION['code']);

if($cc==$ss){

echo "yes";

}else{

echo "no";

}

}