[рони]

drey84,

var arr = [1,2,2,1,1,1,1,1,0,0,0,0,2,1,1,2,0,0,2,1];
function foo(b, c) {
    return b.reduce(function(a, b) {
        a.temp = b == c ? ++a.temp : 0;
        a.temp > a.max && (a.max = a.temp);
        return a
    }, {
        temp: 0,
        max: 0
    }).max
};
alert(foo(arr,0))