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<!DOCTYPE html> <html> <body> <h1>演示如何访问 OPTGROUP 元素</h1> <select size="4"> <optgroup id="myOptgroup" label="Chinese cars"> <option value="byd">BYD</option> <option value="geely">GEELY</option> <option value="gwm">GWM</option> </optgroup> </select> <p>单击按钮可获取选项组的标签/说明。</p> <button onclick="myFunction()">试一试</button> <p id="demo"></p> <script> function myFunction() { var x = document.getElementById("myOptgroup").label; document.getElementById("demo").innerHTML = x; } </script> </body> </html>