ES5 Array新方法lastIndexOf使用实例页面

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)