html页面:
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
<body>
<form action="reg.php" method="post" >
用户名 : <input id="input1" type="text" name="username">
<input type="submit" value="注册">
</form>
<div id="div1"></div>
<script>
var oInput = document.getElementById('input1');
var oDiv = document.getElementById('div1');
oInput.onblur = function(){
var xhr = new XMLHttpRequest();
xhr.open('GET','ajax.php?username='+encodeURIComponent(this.value),true);
xhr.onreadystatechange = function(){
if(xhr.readyState == 4){
if(xhr.status == 200){
var obj = JSON.parse(xhr.responseText);
if(obj.code){
oDiv.innerHTML = obj.message;
}
else{
oDiv.innerHTML = obj.message;
}
}
}
};
xhr.send(null);
};
</script>
</body>
</html>
php页面:
<?php
header('Content-type:text/html;charset=utf-8');
$conn = mysqli_connect('127.0.0.1', 'root', '5221107073', 'linshi');
$name = $_GET['username'];
$sql = "SELECT * FROM shi where name='$name'";
$res = mysqli_query($conn, $sql);
if($res && mysqli_num_rows($res)){
echo "{'code':'0','message':'该名字有人注册'}";
}else{
echo "{'code':'1','message':'ok'}";
}
?>
就是不能从服务端获取到json数据,报错如下:
SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data
求解
header的设置不对,这样设置输出的是utf-8格式的html,
使用
这样echo的数据即为json格式,
建议将要输出的内容存进数组,在要输出的地方使用