<html><head><meta charset="utf-8"><title>手册网教程(shouce.ren)</title></head><body><p>点击按钮后对数组元素进行四舍五入并计算总和。</p><button onclick="myFunction()">点我</button><p>数组元素之和: <span id="demo"></span></p><script>var numbers = [15.5, 2.3, 1.1, 4.7];function getSum(total, num) { return total + Math.round(num);}function myFunction(item) { document.getElementById("demo").innerHTML = numbers.reduce(getSum, 0);}</script></body></html>