js文件先后顺序加载的问题

<script type="text/javascript">
        function loadScript(url, callback) {
           var _script = document.createElement("script");
               _script.type="text/javascript";
               
            if (_script.readyState) {//IE
                _script.onreadystatechange = function () {
                   if (_script.readyState == "loaded" || _script.readyState == "complete") {
                       _script.onreadystatechange = null;
                       callback();
                     }
                };
             }else{
                 _script.onload = function () {//非IE
                     callback();
                 };
             }
                _script.src=url;
                document.getElementsByTagName("head")[0].appendChild(_script);
         };
       
         loadScript("js/jquery-1.10.1.min.js", function () {
                 
             loadScript("js/idangerous.swiper.js", function () {
                 
                 loadScript("js/BaccChartParse.js", function () {
                     
                     loadScript("js/textjs.js", function () {
                         
                     });
                 });
             });
         });
   
</script>