最简单的PHP Ajax案例

$(document).ready(function(){
$('#submit').click(function(){
$.get(
'show.php',
{text:$("#text").val()},{ success:
function(data)
{
alert(data);
var tijiao='';
eval("tijiao="+data+";");
$('#show').html(tijiao);
}
}
);
});
});

<form id="input" name="input" >
<input type="text" name="text" id="text" /><br />
<input type="submit" id="submit" value="提交"/><br />
</form>

<?php
$arr=$_GET;
echo $arr['text'];
?>