php、jquery、ajax、json

json.html

<script type="text/javascript" src="jquery.js"></script> 
<script>
$(function(){      
        $.getJSON("test.php","name=john&sex=boy", function(json){  
			//$.getJSON("test.php?name=john&sex=boy", function(json)
			//$.getJSON("test.php",{name: "John", sex: "boy"}, function(json)
            $("#name").val(json.name); 
            $("#sex").val(json.sex); 
       });  
}); 
</script>
<div id="OK"></div>
name:<input id="name" type="text"/><br/>
sex:<input id="sex" type="text"/></a><br/>

 test.php

<?php
$name=$_GET[name]; 
$sex=$_GET[sex]; 
$list=array("name"=>$name,"sex"=>$sex); 
echo $encode= json_encode($list);

 ajax

$.ajax({
	type:'POST',
	url:'chk.php?username=' + username,
	data:'',
	success:function(obj){
		if(obj == '1'){
			return false;
		}
		else{
			return true;
		}
	}
});

 chk.php

$username = $_REQUEST['username'];
if ($username=="hello") {
	echo "1";
}else{
	echo '0';
}