# Date.toISOString()
The toISOString() method returns a string in simplified extended ISO format (ISO 8601), which is always 24 or 27 characters long (YYYY-MM-DDTHH:mm:ss.sssZ or ±YYYYYY-MM-DDTHH:mm:ss.sssZ, respectively)
```javascript
var event = new Date('05 October 2011 14:48 UTC');
console.log(event.toString());
// expected output: Wed Oct 05 2011 16:48:00 GMT+0200 (CEST)
// (note: your timezone may vary)
console.log(event.toISOString());
// expected output: 2011-10-05T14:48:00.000Z
```
## Syntax
```javascript
dateObj.toISOString()
```
**Return value**
A string representing the given date in the [ISO 8601](http://en.wikipedia.org/wiki/ISO_8601) format according to universal time.
## Examples
#### Using `toISOString()`
```javascript
var today = new Date('05 October 2011 14:48 UTC');
console.log(today.toISOString()); // Returns 2011-10-05T14:48:00.000Z
```
The above example uses parsing of a non–standard string value that may not be correctly parsed in non–Mozilla browsers.
## Polyfill
This method was standardized in ECMA-262 5th edition. Engines which have not been updated to support this method can work around the absence of this method using the following shim:
```javascript
if (!Date.prototype.toISOString) {
(function() {
function pad(number) {
if (number < 10) {
return '0' + number;
}
return number;
}
Date.prototype.toISOString = function() {
return this.getUTCFullYear() +
'-' + pad(this.getUTCMonth() + 1) +
'-' + pad(this.getUTCDate()) +
'T' + pad(this.getUTCHours()) +
':' + pad(this.getUTCMinutes()) +
':' + pad(this.getUTCSeconds()) +
'.' + (this.getUTCMilliseconds() / 1000).toFixed(3).slice(2, 5) +
'Z';
};
}());
}
```
## References
{% embed url="" %}
## Contributors to this page
Uros Durdevic