js 动态加载不同类型的文件包括css，js

var dynamicLoading = {
  css: function(path){
 if(!path || path.length === 0){
  throw new Error('argument "path" is required !');
 }
 var head = document.getElementsByTagName('head')[0];
    var link = document.createElement('link');
    link.href = path;
    link.rel = 'stylesheet';
    link.type = 'text/css';
    head.appendChild(link);
  },
  js: function(path){
 if(!path || path.length === 0){
  throw new Error('argument "path" is required !');
 }
 var head = document.getElementsByTagName('head')[0];
    var script = document.createElement('script');
    script.src = path;
    script.type = 'text/javascript';
    head.appendChild(script);
  }
}
dynamicLoading.css(strpath);
dynamicLoading.js(strpath);//填写相对路径