JSON语法的问题，如何理解for循环那里

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>task_24_01</title>
</head>
<body>
<button id="btn">点我</button>
<script>
function ajax (opts) {
var xhr = new XMLHttpRequest ()
xhr.onreadystatechange = function () {
if (xhr.readyState === 4 && xhr.status === 200) {
var json = JSON.parse(xhr.responseText);
opts.success(json)
}
if (xhr.readyState === 4 && xhr.status === 404) {
opts.error()
}
};

var dataStr = "";
for (var key in opts.data) {
dataStr += key + '=' + opts.data[key] + '&'
}
dataStr = dataStr.substr(0, dataStr.length - 1);
if (opts.type.toLowerCase() === 'get') {
xhr.open(opts.type, opts.url + '?' + dataStr, true);
xhr.send()
}
if(opts.type.toLowerCase() === 'post') {
xhr.open(opts.type, opts.url, true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.send(dataStr)
}
}
document.querySelector('#btn').addEventListener('click', function(){
btn = document.querySelector('#btn');
btn.innerHTML = '正在打印';
ajax({
url: 'getData.php', //接口地址
type: 'get', // 类型， post 或者 get,
data: {
username: 'xiaoming',
password: 'abcd1234'
},
success: function(ret){
console.log(ret); // {status: 0}
btn.innerHTML = '点我'
},
error: function(){
console.log('出错了');
btn.innerHTML = '点我'
}
})
});
</script>
</body>
</html>

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3回答

一瞬儿光

这都是啥东西？

0 0

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