JavaScript数组求和与最大值获取：循环与reduce方法详解

Array.prototype.sum = function (){
 var result = 0;
 for(var i = 0; i < this.length; i++) {
  result += this[i];
 }
 return result;
};

[1,4,7,2,10].sum(); // 24

array.reduce(callback[, initialValue]);

Array.prototype.sum = function (){
 return this.reduce(function (partial, value){
  return partial + value;
 })
};
[1,4,7,2,10].sum(); // 24

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />

<title>本站_js数组求和和最大值方法_本站网</title>

<meta name="keywords" content="站长,网页特效,网页特效代码,js特效,js脚本,脚本,广告代码,jb51.net,www.jb51.net,本站网" />

<meta name="description" content="www.jb51.net,本站网，站长必备js特效及广告代码。大量高质量js特效，提供高质量广告代码下载,尽在本站网" />

</head>

<body>

<a href="https://www.jb51.net/">本站网</a>,站长必备的高质量网页特效和广告代码。jb51.net，站长js特效。<hr>

<script type="text/javascript">

//求和

Array.prototype.sum = function () {

 for (var sum = i = 0; i < this.length; i++)sum += parseInt(this[i]);

  return sum ;

};

//求最大值

Array.prototype.maxima = function () {

 for (var i = 0, maxValue = Number.MIN_VALUE; i < this.length; i++)parseInt(this[i]) > maxValue && (maxValue = this[i]);

 return maxValue;

};

//应用

var arr = [1,21,3,4,22,45,60,7,32];

alert(arr.join("+") + "=" + arr.sum()); alert(arr.join("|") + "中, 最大的数是:" + arr.maxima());

</script>

</body>

</html>