<!DOCTYPE html>charset="utf-8"W3Cschool教程(w3cschool.cn)id="demo"单击按钮显示从位置4开始查找的“苹果”第一次出现的位置:onclick="myFunction()"点我function myFunction(){var fruits=["Banana","Orange","Apple","Mango","Banana","Orange","Apple","Mango"];var a=fruits.indexOf("Apple",4)var x=document.getElementById("demo");x.innerHTML=a;}注意:indexOf方法是在JavaScript 1.6中被引进的,在IE 8 或更早的版本中不支持。