摘要：
遍历json数组并动态添加选项进行选择，然后直接编码。重要部件有注释˂！
遍历json数组 并动态为select添加option
直接上代码，重要部分有注解
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1,user-scalable=0,viewport-fit=cover">
<link rel="stylesheet" href="https://res.wx.qq.com/open/libs/weui/1.1.2/weui-for-work.css">
<script type="text/javascript" src="http://t.zoukankan.com/lib/zepto.min.js"></script>
<script type="text/javascript" src="http://t.zoukankan.com/lib/jquery-1.9.1.min.js"></script>
<title>任务发布</title>
</head>
<body>
<form method="post" action="">
<div style="margin-top: 30px">项目名称</div>
<div class="weui-cells">
<div class="weui-cell">
<select name="pro_id" id="sel">
</select>
</div>
</div>
<div style="margin-top: 30px">任务名称</div>
<div class="weui-cells">
<div class="weui-cell">
<div class="weui-cell__bd">
<input type="text" placeholder="请输入任务名称" name="task_name"/>
</div>
</div>
</div>
<div style="margin-top: 30px">任务内容</div>
<div class="weui-cells weui-cells_form">
<div class="weui-cell">
<div class="weui-cell__bd">
<textarea placeholder="请输入内容" rows="7" name="task_content"></textarea>
</div>
</div>
</div>
<div style="margin-top: 30px">任务期限</div>
<div class="weui-cells weui-cells_form">
<div class="weui-cell">
<div class="weui-cell__hd"><label class="weui-label">时间</label></div>
<div class="weui-cell__bd">
<input type="datetime-local" value="" placeholder="" name="task_time"/>
</div>
</div>
</div>
<div style="margin-top: 30px">任务级别</div>
<div class="weui-cells weui-cells_radio">
<label for="x11">
<div class="weui-cell__bd">
<p>高</p>
</div>
<div class="weui-cell__ft">
<input type="radio" name="radio1" value="2"/>
<span class="weui-icon-checked"></span>
</div>
</label>
<label for="x12">
<div class="weui-cell__bd">
<p>中</p>
</div>
<div class="weui-cell__ft">
<input type="radio" name="radio1" checked="checked" value="1"/>
<span class="weui-icon-checked"></span>
</div>
</label>
<label for="x13">
<div class="weui-cell__bd">
<p>低</p>
</div>
<div class="weui-cell__ft">
<input type="radio" name="radio1" checked="checked" value="0"/>
<span class="weui-icon-checked"></span>
</div>
</label>
</div>
<div style="margin-top: 30px ;padding-bottom: 100px">
<input onclick="sub()" value="确定" type="submit"/>
</div>
</form>
<script type="text/javascript">
/**
* 使用ajax获取服务器json 数组
*/
var httpRequest = new XMLHttpRequest();
httpRequest.open('GET', 'http://www.-------', true);
/**
* 获取数据后的处理程序
*/
httpRequest.onreadystatechange = function () {//固定写法
if (httpRequest.readyState == 4 && httpRequest.status == 200) {//固定写法
var json = httpRequest.responseText;//获取到json字符串，还需解析
var obj = JSON.parse(json);//解析字符串---解析成object数组
for (var i = 0; i < obj.length; i++) {
var pro = obj[i];
document.getElementById("sel").options.add(new Option(pro.corp_name, pro.project_id));//使用纯js为select动态添加option
}
}
}
httpRequest.send();
</script>
</body>
</html>