ES5 Array新方法lastIndexOf使用实例页面
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HTML代码:
<p id="result"></p>
JS代码:
var eleResult = document.getElementById("result"); if (!window.console) { window.console = {}; } console.log = function(result) { var text = document.createTextNode(result), br = document.createElement("br"); eleResult.appendChild(text); eleResult.appendChild(br); }; if (typeof Array.prototype.lastIndexOf != "function") { Array.prototype.lastIndexOf = function (searchElement, fromIndex) { var index = -1, length = this.length; fromIndex = fromIndex * 1 || length - 1; for (var k = length - 1; k > -1; k-=1) { if (k <= fromIndex && this[k] === searchElement) { index = k; break; } } return index; }; } var data = [2, 5, 7, 3, 5]; console.log(data.lastIndexOf(5)); // 4 console.log(data.lastIndexOf(5, 3)); // 1 (从3号位开始搜索) console.log(data.lastIndexOf(4)); // -1 (未找到)
结果:
4
1
-1