正则

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    <script>
        let str = `"<p><img id="1630633989830-0" style=" 100%; height: auto; display: block;" src="https://wxyl.pension.taikang.com/WX/activity/BGCZone/21/headImg.png" /></p>
            <p><img id="1630633961028" style=" 100%; height: auto; display: block;"   src="https://wxyl.pension.taikang.com/WX/tkp-activity/2021/09/02/FC74D1F61AB04E5F84C8DDBCE896970F.png"  data-poster="http://p5-tkpes-tkgrowth-1305527481.cos.ap-beijing.myqcloud.com/tkpvideo/e9f2f5e6e2b644b483579492ff4c7933.mp4" /><img id="1630634039423-0" style=" 100%; height: auto; display: block;" src="https://wxyl.pension.taikang.com/WX/activity/BGCZone/21/desc.jpg" />你好</p>
        <p>&nbsp;</p>"`

     /*   let arr = str.match(/.*src="(.*)"[ ]+data-poster="(.*)"[ ]+/></)
        console.log(arr);*/

/*        let arr = str.match(/<imgs*.*data-posters*="(.*mp4)"s/>/) 
        console.log(arr);*/
        //匹配 <img 任意字符零次到多次 src="(任意字符)" 空格最少一次 data-poster="(任意字符mp4)" 空格零次或多次 />
        let arr = str.match(/<img .* src="(.*)"s+data-poster="(.*mp4)"s*/>/)
        console.log(arr);

 /*       .* 表示 单个字符匹配任意次数  
         .*? 是满足条件的情况只匹配一次,即最小匹配.
  */
    </script>
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原文地址:https://www.cnblogs.com/javascript9527/p/15226749.html