Parse any number string to float

function stringToFloat(str) {
    var fractional_part, integer, fractional = "", found = false, i;
    // remove leading and trailing non-digit symbols
    str = str.replace(/[^\d,\.]+$/, '').replace(/^[^\d,\.]+/, '');
    fractional_part = str.slice(-3);
    for (i = fractional_part.length - 1; i >= 0; i--) {
        if (/\d/.test(fractional_part[i])) {
            fractional = fractional_part[i] + fractional;
        } else {
            found = true;
            break;
        }
    }
    if (fractional && found) {
        integer = str.slice(0, i - 3);
    } else {
        integer = str;
        fractional = "";
    }
    return parseFloat(integer.replace(/[^\d]/g, '') + "." + fractional);
}