jQuery начинается с селектора

function test() {
    var foo = [];
    $('#tree table').each(function(i, table) {
        foo[i] = $(table).text().trim();
    });

    var ch = 'G';

    for (j = 0; j <= 12; j++) {
        if (foo[j] ^= ch) {
            alert(foo[j]);
        }
    }
}

[foo[j] ^= ch] startsWith selector isn't working in the above code. Help needed. Couldn't find any answer. Thanks in adv.