function fn(){
    console.log(11111);
    function setHtmlFontSize() {
        let whdef = 100 / 1920 ;
        let bodyWidth = document.documentElement.getBoundingClientRect().width;
        console.log(bodyWidth,'屏幕宽度')
        let rem = bodyWidth * whdef
        document.getElementsByTagName('html')[0].style.fontSize = rem + 'px'

    }
    setHtmlFontSize()
    window.addEventListener('resize',function(){
        setTimeout(function(){
            setHtmlFontSize()
        },100)
    })
}
fn()