本文实例讲述了JS实现求数组起始项到终止项之和的方法。分享给大家供大家参考,具体如下:
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<meta charset="UTF-8">
<title>JS求数组之和</title>
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[removed]
Array.prototype.sum= function(l,r){
l=l==undefined ? 0 : l;
r=r==undefined ? this.length - 1 : r;
var s = 0;
for(var i = l;i <= r;i++){s+=this[i