express解决跨域post请求变成OPTIONS

在app.js中加入以下代码：

代码如下：
app.all(’’, function(req, res, next) {
res.header(“Access-Control-Allow-Origin”, "");
res.header(“Access-Control-Allow-Headers”, “X-Requested-With,Content-Type”);
res.header(“Access-Control-Allow-Methods”,“PUT,POST,GET,DELETE,OPTIONS”);
next();
});