JavaScript implements dragging and replacing web page block elements_javascript skills

I looked for some ready-made plug-ins and found that none of them met my needs, so I implemented one myself by referring to examples on the Internet, but it has not been optimized yet.

Let’s post the code:
dragtoreplace

<title>DragToReplaceDeom</title> <style> #displayRoom{background:#eee;position:relative;float:left;clear:both;padding:30px 0px 0px 20px;margin-left:20px;margin-top:10px;} .row{display:inline-block;float:left;width:90px;clear:none;top:0;/**//*background:#DFEFFC;*/} .row span{display:inline-block;width:60px;clear:none;background:#9192B1;height:30px;line-height:30px;margin-bottom:30px;text-align:center;} span.usr{cursor:pointer;position:absolute;display:inline-block;width:60px;clear:none;height:30px;line-height:30px;margin-bottom:30px;text-align:center;background:#4DA74D;color:#fff;} span.usr.catch{background:#BD9B33!important;} </style> <div id="displayRoom"> <div class="row"> <span><span class="usr" id="345">Student A</span></span><span></span><span></span><span></span> </div> <div class="row"> <span><span class="usr" id="123">Student B</span></span><span id="3"></span><span></span><span></span> </div> <div class="row"> <span></span><span></span><span></span><span></span> </div> <div class="row"> <span></span><span><span class="usr" id="456">Student One</span></span><span></span><span></span> </div> </div>
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