rem适配

//REM适配
new function() {
var _self = this;
_self.width = 640; // 设置默认最大宽度
_self.fontSize = 100; // 默认字体大小
_self.widthProportion = function() {
var p = (document.body && document.body.clientWidth || document.getElementsByTagName("html")[0].offsetWidth) / _self.width;
return p > 1 ? 1 : p < 0.5 ? 0.5 : p;
};
_self.changePage = function() {
document.getElementsByTagName("html")[0].setAttribute("style", "font-size:" + _self.widthProportion() * _self.fontSize + "px !important; display:block");
}
_self.changePage();
window.addEventListener('resize', function() {
_self.changePage();
}, false);
};