function myIsDate(mystring)
{//--BOF 
var mystring, myresult ;
var mystring = new Date(mystring);
isNaN(mystring)? myresult=false : myresult=true ;
return myresult ;
//--EOF
}
//我的测试
  alert(IsDate('2009/10/10'));  //true
  alert(IsDate('2010/07/00'));  //true
  alert(IsDate('2009/02/30'));  //true
  alert(IsDate('200k/10/10'));  //false
  alert(IsDate('2009/13/10'));  //true
  alert(IsDate('200k-10-10'));  //false
//失败

function isDate (value)
{
return (!isNaN (new Date (value).getYear () ) ) ;
}
//我的测试
  alert(IsDate('2009/10/10'));  //true
  alert(IsDate('2010/07/00'));  //true
  alert(IsDate('2009/02/30'));  //true
  alert(IsDate('200k/10/10'));  //false
  alert(IsDate('2009/13/10'));  //true
  alert(IsDate('200k-10-10'));  //false
//失败

// 这个可以，稍微改改，加上匹配'2010-01-10'就好了。
// ******************************************************************
// This function accepts a string variable and verifies if it is a
// proper date or not. It validates format matching either
// mm-dd-yyyy or mm/dd/yyyy. Then it checks to make sure the month
// has the proper number of days, based on which month it is.

// The function returns true if a valid date, false if not.
// ******************************************************************

function isDate(dateStr) {

var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/;
var matchArray = dateStr.match(datePat); // is the format ok?

if (matchArray == null) {
alert("Please enter date as either mm/dd/yyyy or mm-dd-yyyy.");
return false;
}

month = matchArray[1]; // p@rse date into variables
day = matchArray[3];
year = matchArray[5];

if (month < 1 || month > 12) { // check month range
alert("Month must be between 1 and 12.");
return false;
}

if (day < 1 || day > 31) {
alert("Day must be between 1 and 31.");
return false;
}

if ((month==4 || month==6 || month==9 || month==11) && day==31) {
alert("Month "+month+" doesn`t have 31 days!")
return false;
}

if (month == 2) { // check for february 29th
var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (day > 29 || (day==29 && !isleap)) {
alert("February " + year + " doesn`t have " + day + " days!");
return false;
}
}
return true; // date is valid
}

function IsDate(dateval){
    var arr = new Array();

    if(dateval.indexOf("-") != -1){
        arr = dateval.toString().split("-");
    }else if(dateval.indexOf("/") != -1){
        arr = dateval.toString().split("/");
    }else{
        return false;
    }

    //yyyy-mm-dd || yyyy/mm/dd
    if(arr[0].length==4){
        var date = new Date(arr[0],arr[1]-1,arr[2]);
        if(date.getFullYear()==arr[0] && date.getMonth()==arr[1]-1 && date.getDate()==arr[2]){
            return true;
        }
    }
    //dd-mm-yyyy || dd/mm/yyyy
    if(arr[2].length==4){
        var date = new Date(arr[2],arr[1]-1,arr[0]);
        if(date.getFullYear()==arr[2] && date.getMonth()==arr[1]-1 && date.getDate()==arr[0]){
            return true;
        }
    }
    //mm-dd-yyyy || mm/dd/yyyy
    if(arr[2].length==4){
        var date = new Date(arr[2],arr[0]-1,arr[1]);
        if(date.getFullYear()==arr[2] && date.getMonth()==arr[0]-1 && date.getDate()==arr[1]){
            return true;
        }
    }

    return false;
}
  alert(IsDate('2009/10/10'));  //true
  alert(IsDate('2010/07/00'));  //false
  alert(IsDate('2009/02/30'));  //false
  alert(IsDate('200k/10/10'));  //false
  alert(IsDate('2009/13/10'));  //false
  alert(IsDate('200k-10-10'));  //false
  alert(IsDate('2000-02-29'))   //true
  alert(IsDate('2100-02-29'))   //true
//就是你了

//匹配//yyyy-mm-dd || yyyy/mm/dd  
function