ktyr report

const options = {
   method  : "HEAD"
};
fetch(elm.href,options)
    .then((response)=>{
        if (!response.ok) {
            throw new Error();
        }
        return response;
    })
    .then((response)=>{
        const fileSize = response.headers.get("Content-Length");
        if(fileSize) {
            console.log(fileSize);
        }else{
            throw new Error();
        }
    })
    .catch((error)=>{
    });