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<!DOCTYPE html> <html> <body> <form> <select id="mySelect" size="8"> <option>苹果</option> <option>桃子</option> <option>香蕉</option> <option>桔子</option> </select> </form> <br> <p>单击该按钮可在下拉列表的索引位置“2”（“香蕉”之前）添加一个“猕猴桃”选项。</p> <button type="button" onclick="myFunction()">插入选项</button> <script> function myFunction() { var x = document.getElementById("mySelect"); var option = document.createElement("option"); option.text = "猕猴桃"; x.add(option, x[2]); } </script> </body> </html>