H5页面字体大小使用rem （重置字体大小）setFontSize.js

html字体大小要先设置成100px，并且JS在CSS重置为100px以后引入。

//初始化rem
(function(){
var getStyle = (function(){
if(window.currentStyle){
return function(obj, name){
return obj.currentStyle[name];
}
}
else{
return function(obj, name){
return getComputedStyle(obj, false)[name];
}
}
})();

var addEvent = (function(){
if(document.attachEvent){
return function(obj, ev, fn){
obj.attachEvent('on'+ev, fn);
};
}
else{
return function(obj, ev, fn){
obj.addEventListener(ev, fn, false);
};
}
})();

var oHtml = document.querySelector('html');
var fontSize = getStyle(oHtml, 'fontSize').split('px')[0];
var originalWidth = 750;

setFontSize();

addEvent(window, 'resize', function(){
setFontSize();
});

function setFontSize() {
var size = size || 200;
var _fontSize = (getSize()['width'] * fontSize / 750)>size?size:(getSize()['width'] * fontSize / 750);
oHtml.style.fontSize = _fontSize + "px";
}

function getSize() {
return {
width :document.documentElement.clientWidth || document.body.clientWidth,
height :document.documentElement.clientHeight || document.body.clientHeight
}
}
})();