Click on the hyperlink in js to prompt a layer. Click on the blank layer to disappear_javascript skills

Please tell me. Click on the hyperlink and a layer will be prompted. Click on the blank space and the layer will disappear.

Native js version

<title>Tips</title> <meta http-equiv="content-type" content="text/html; charset=gbk"> <style type="text/css"> BODY { BACKGROUND: #fff; FONT: 76%/1.5 Arial,sans-serif; COLOR: #333 } input{ width:200px;border: 1px solid #86B9D6; } #reg_div{ color: #154BA0; border: 1px solid #86B9D6; background: #D9EEF9; position: absolute; z-index: 30; height: 180px; width:400px; } .city{ width:80px; float:left; padding:8px; text-align:center; } .ps_div{ padding:10px 10px 2px 10px; border-bottom:1px dotted #ccc; } </style> <input id="input_01" type="text" onfocus="allt(this);"> <div id="reg_div" style="display:none"> <div class="ps_div"> <span style="float:right;" onclick="oo('reg_div').style.display='none'"> </span> </div>Close<div id="city_01" class="city" onclick="bllt(this)">Find tips:</div> <div id="city_02" class="city" onclick="bllt(this)">Beijing</div> <div id="city_03" class="city" onclick="bllt(this)">Shanghai</div> <div id="city_04" class="city" onclick="bllt(this)">Guangzhou</div> <div id="city_01" class="city" onclick="bllt(this)">Shenzhen</div> <div id="city_02" class="city" onclick="bllt(this)">Hangzhou</div> <div id="city_03" class="city" onclick="bllt(this)">Nanjing</div> <div id="city_04" class="city" onclick="bllt(this)">Chengdu</div> <div id="city_01" class="city" onclick="bllt(this)">Wuhan</div> <div id="city_02" class="city" onclick="bllt(this)">Qingdao</div> <div id="city_03" class="city" onclick="bllt(this)">Dalian</div> <div id="city_04" class="city" onclick="bllt(this)">Chongqing</div> <div id="city_01" class="city" onclick="bllt(this)">Sanya</div> <div id="city_02" class="city" onclick="bllt(this)">Zhengzhou</div> <div id="city_03" class="city" onclick="bllt(this)">Ningbo</div> <div id="city_04" class="city" onclick="bllt(this)">Xi鈥檃n</div> </div>Changsha