判断是否为正确日期格式的javascript

function isDateString(sDate) {

    var iaMonthDays = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

    var iaDate = new Array(3)

    var year, month, day

    iaDate = sDate.toString().split("-")

    if (iaDate.length != 3) return false

    if (iaDate[1].length > 2 || iaDate[2].length > 2) return false

    year = parseFloat(iaDate[0])

    month = parseFloat(iaDate[1])

    day = parseFloat(iaDate[2])

    if (year < 1900 || year > 2100) return false

    if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) iaMonthDays[1] = 29;

    if (month < 1 || month > 12) return false

    if (day < 1 || day > iaMonthDays[month - 1]) return false

    return true

}