if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (searchElement, fromIndex) {
        if ( this === undefined || this === null ) {
            throw new TypeError( '"this" is null or not defined' );
        }

        var length = this.length >>> 0; // Hack to convert object.length to a UInt32

        fromIndex = +fromIndex || 0;

        if (Math.abs(fromIndex) === Infinity) {
            fromIndex = 0;
        }

        if (fromIndex < 0) {
            fromIndex += length;
            if (fromIndex < 0) {
                fromIndex = 0;
            }
        }

        for (;fromIndex < length; fromIndex++) {
            if (this[fromIndex] === searchElement) {
                return fromIndex;
            }
        }

        return -1;
    };
}
Add Array.indexOf polyfill for IE8
Add Array.indexOf polyfill for IE8
