Question

I’m trying to build a little calendar in JavaScript. I have my dates working great in Firefox and Chrome, but in IE the date functions are returning NaN.

Here is the function :

function buildWeek(dateText){
    var headerDates='';
    var newDate = new Date(dateText);

    for(var d=0;d<7;d++){
        headerDates += '<th>' + newDate + '</th>';
        newDate.setDate(newDate.getDate()+1);
    }                       

    jQuery('div#headerDates').html('<table><tr>'+headerDates+'</tr></table>');
}

dateText is the Monday of the current week which is actually set in php in the format of ‘m, d, Y’, e.g. "02, 01, 2010".

Answer 1

The Date constructor accepts any value. If the primitive [[value]] of the argument is number, then the Date that is created has that value. If primitive [[value]] is String, then the specification only guarantees that the Date constructor and the parse method are capable of parsing the result of Date.prototype.toString and Date.prototype.toUTCString()

A reliable way to set a Date is to construct one and use the setFullYear and setTime methods.

An example of that appears here:
http://jibbering.com/faq/#parseDate

ECMA-262 r3 does not define any date formats. Passing string values to the Date constructor or Date.parse has implementation-dependent outcome. It is best avoided.

---

Edit:
The entry from comp.lang.javascript FAQ is:
An Extended ISO 8601 local date format YYYY-MM-DD can be parsed to a Date with the following:-

/**Parses string formatted as YYYY-MM-DD to a Date object.
 * If the supplied string does not match the format, an 
 * invalid Date (value NaN) is returned.
 * @param {string} dateStringInRange format YYYY-MM-DD, with year in
 * range of 0000-9999, inclusive.
 * @return {Date} Date object representing the string.
 */

  function parseISO8601(dateStringInRange) {
    var isoExp = /^\s*(\d{4})-(\d\d)-(\d\d)\s*$/,
        date = new Date(NaN), month,
        parts = isoExp.exec(dateStringInRange);

    if(parts) {
      month = +parts[2];
      date.setFullYear(parts[1], month - 1, parts[3]);
      if(month != date.getMonth() + 1) {
        date.setTime(NaN);
      }
    }
    return date;
  }