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Ben Nadel
On User Experience (UX) Design, JavaScript, ColdFusion, Node.js, Life, and Love.

Demonstration Of Date Object Formatting Using Date Prototyping

By Ben Nadel on

If anyone is interested, I put together this little demo for a dude who posted a comment on my site. It demonstrates how to apply a date and time mask to a Javascript Date object using regular expressions. It creates two methods that are prototyped to the Javascript Date object and therefore are available to all dates:

  • Date.prototype.dateFormat()
  • Date.prototype.timeFormat()

Regular Expression Date Mask Demo

Reader Comments

Hey, by the way there is what I would consider to be a "bug" in this. getMonth() is a zero based function, so months like January come back as 0 and December comes back as 11. It can be fixed like this:

"m": this.getMonth()+1,
"mm": ((this.getMonth()+1).toString().length == 1) ? ("0" + this.getMonth()+1) : this.getMonth()+1,


Thanks for the update. It seems to be handled differently in every language, so I am hesitant to call anything a bug. However, a zero-based month system never feels natural. You just want to say FIRST month (as in 1st as in 1) of the year.