JS---依赖加载简单实现方式

function loadScript(url, callback) {
  var script = document.createElement("script");
  script.type = "text/javascript";
  script.src = url;
  document.getElementById("srciptCode").appendChild(script);
  script.onload = function() {
    callback();
  }
}
loadScript("../js/jquery-1.8.3.min.js",function(){
  console.log("jquery-1.8.3.min.js ok")
  loadScript("../js/jquery.qrcode.min.js",function(){
    console.log("jquery.qrcode.min.js ok")
    loadScript("../js/ui.min.js?0107",function(){
      console.log("ui.min.js ok")
      loadScript("../js/activity/code.min.js?0107",function(){
        console.log("code.min.js ok")
      })
    })
  })
})