var obj = new WxLogin({
      id:"login_container", 
      appid: "", 
      scope: "", 
      redirect_uri: "",
      state: "",
      style: "",
      href: "../qrcode.css"//就是这个属性
      });

var fs = require('fs');
// function to encode file data to base64 encoded string
function base64_encode(file) {
 // read binary data
 var bitmap = fs.readFileSync(file);
 // convert binary data to base64 encoded string
 return 'data:text/css;base64,'+new Buffer(bitmap).toString('base64');
}
console.log(base64_encode('./qrcode.css'))

var obj = new WxLogin({
      id:"login_container", 
      appid: "", 
      scope: "", 
      redirect_uri: "",
      state: "",
      style: "",
           href:"data:text/css;base64,LmltcG93ZXJCb3ggLnFyY29kZSB7d2lkdGg6IDIwMHB4O30NCi5pbXBvd2VyQm94IC50aXRsZSB7ZGlzcGxheTogbm9uZTt9DQouaW1wb3dlckJveCAuaW5mbyB7d2lkdGg6IDIwMHB4O30NCi5zdGF0dXNfaWNvbiB7ZGlzcGxheTpub25lf
Q0KLmltcG93ZXJCb3ggLnN0YXR1cyB7dGV4dC1hbGlnbjogY2VudGVyO30="//data-url
      });