h5页面宽度设置7.5rem

function ready() {

                var u = navigator.userAgent;

                var winW = document.documentElement.clientWidth;

                if (!!!u.match(/AppleWebKit.*Mobile.*/)) {

                    winW = 414;

                    document.getElementsByClassName('wraper')[0].style.width = '' + winW + 'px';

                }

                document.documentElement.style.fontSize = winW / 7.5 + 'px';

            }

            ready();

            window.addEventListener("resize", ready, false);