js一键复制方法

 <div id="copyId">
        复制的内容
    </div>
    <button type="button" onclick="copy()">一键复制</button>

    <script>

        function copy() {
            var val = document.getElementById('copyId');
            window.getSelection().selectAllChildren(val);
            document.execCommand("Copy");
        }
    </script>

  <div id="xxxx">2713549</div>
  <button onclick="copyText()">复制</button>
  <script>


      function copyText(target) {
          document.querySelector("#xxxx").innerHTML=parseInt(Math.random()*10000000)
          var div = document.getElementById('xxxx');
          if (document.body.createTextRange) {
              console.log(1);
              var range = document.body.createTextRange();
              range.moveToElementText(div);
              range.select();
              document.execCommand("Copy"); // 执行浏览器复制命令
              // alert("已复制好，可贴粘。");
              selection.removeAllRanges();
          } else if (window.getSelection) {
              console.log(2);
              var selection = window.getSelection();
              var range = document.createRange();
              range.selectNodeContents(div);
              selection.removeAllRanges();
              selection.addRange(range);
              document.execCommand("Copy"); // 执行浏览器复制命令
              // alert("已复制好，可贴粘。");
              window.getSelection().removeAllRanges()
          } else {
              console.warn("none");
          }
      }
  </script>