function  randomImage (max) {
    var bannerList = '';

    for( var i = 0; i < max; i++){
        var k = Math.floor(Math.random() * banners.length);

        if (i % 2 == 0) {
            bannerList += '<li><a href="plan/' + banners[k].link + '"><img src="common/image/index/contents/' + banners[k].image + '" alt="' + banners[k].name + '"></a></li>';
        }
        else {
            bannerList += '<li style="margin-right: 0;"><a href="plan/' + banners[k].link + '"><img src="common/image/index/contents/' + banners[k].image + '" alt="' + banners[k].name + '"></a></li>';
        }
        banners.remove(k);
    }

    document.getElementById('banners').innerHTML = bannerList;
}

/*
 for Mac IE
 remove(k) は splice(k, 1) と同じ働きをします。
*/

Array.prototype.remove = function (k) {
    var newary = [];
    var j = 0;
    for ( var i = 0; i < this.length; i++ ) {
        if ( i != k ) {
            this[j] = this[i];
            j++;
        }
    }

    this.length = this.length - 1;
}

function trigerRandomImage() {
    randomImage(4);
}

if(window.addEventListener) {
    window.addEventListener("load", trigerRandomImage, false);
}
else if(window.attachEvent) {
    window.attachEvent("onload", trigerRandomImage);
}