I didn"t know how to get code
var url=encodeURI ("xxxxx")
window.location.href=" https://open.weixin.qq.com/co." + "appid=xxxxxxx&redirect_uri="+url+"&response_type=code&scope=snsapi_login&state=3d6be0a4035d839573b04816624a415e-sharpwechat_redirect";
after scanning the code, I will jump to the above url. How can I get the code before the jump
how should this callback be written, and where can I get the code to request other parameters