通过传id封装loading

<script type="text/javascript">
    function SearchAnim(opts) {  
      for(var i in SearchAnim.DEFAULTS) {  
          if (opts[i] === undefined) {  
             opts[i] = SearchAnim.DEFAULTS[i];  
          }  
      }  
      this.opts = opts;  
      this.timer = null;  
      this.elem = document.getElementById(opts.elemId); 
      this.startAnim();  
   }  
   SearchAnim.prototype.startAnim = function () {  
      this.stopAnim();  
      this.timer = setInterval(() => {  
      var startIndex = this.opts.startIndex;  
         if (startIndex == 360) {  
            this.opts.startIndex = 0;  
      }  
      this.elem.style.transform = "rotate("+(startIndex)+"deg)";  
            this.opts.startIndex += 5;  
            }, this.opts.delay);  
      
            setTimeout(() => {  
                this.stopAnim();  
            }, this.opts.duration);  
        }  
        SearchAnim.prototype.stopAnim = function() {  
            if (this.timer != null) {  
                clearInterval(this.timer);  
            }  
        }  
        SearchAnim.DEFAULTS = {  
            duration : 60000,  
            delay : 200,  
            direction : true,  
            startIndex : 0,  
            endIndex : 360,
        } 
        new SearchAnim({  
            elemId : "loading",  
            delay : 20,  
        });