JS 数组的删除与判断是否存在的两个扩展方法

Array.prototype.remove = function (dx) {
if (isNaN(dx) || dx > this.length) {
return false;
}
for (var i = 0, n = 0; i < this.length; i++) {
if (this[i] != this[dx]) {
this[n++] = this[i];
}
}
this.length -= 1;
return false;
};

Array.prototype.contains = function (item) {
return RegExp("\\b" + item + "\\b").test(this);
};