Tag Archives: unix timestamp

How to Check if a Date is More or Less Than a Month Ago with PHP

Let’s say we have the following problem: we have to check whether a date is more than a month ago or less than a month ago. Many developers go in the wrong direction by calculating the current month and then subtracting the number of months from it. Of course, this approach is slow and full of risks of allowing bugs. Since, two months before January, which is the first month of the year, is actually November, which is the eleventh month. Because of these pitfalls, this approach is entirely wrong.

strtotime() is a lot more powerful than you think!
strtotime() is a lot more powerful than you think!

The question is whether PHP cannot help us with built-in functions to perform these calculations for us. It is obvious, that from version 5.3.0 and later, there is an OOP section, which is great, but unfortunately this version is still not updated everywhere. So, how to accomplish the task?

The Wrong Approach

As I said, there are many ways to go in the wrong direction. One of them is to subtract 30 days from current date. This is completely wrong, because not every month has 30 days. Here, some developers will begin to predefine arrays to indicate the number of days in each month, which then will be used in their complicated calculations. Here is an example of this wrong approach.

echo date('Y-m-d', strtotime(date('Y-m-d')) - 60*60*24*30);

This line is full of mistakes. First of all strtotime(date(‘Y-m-d’)) can be replaced by the more elegant strtotime(‘now’), but for this later. Another big mistake is that 60*60*24*30, which is number of seconds in 30 days can be predefined as a constant. Eventually the result is wrong, because not every month has 30 days.

The Correct Approach

A small research of the problem and the functions in versions prior of 5.3.0 of PHP is needed. Typical case study of date formatting happen when working with dates from a database. The following code is a classical example. Continue reading How to Check if a Date is More or Less Than a Month Ago with PHP

Flex 3 DateChooser UTC issue

What I intend to do

The task can be described as it is. There’s a Flex 3 DateChooser component integrated with a custom timeline component. The problem occurs when exporting the data from the flash to the browser. Than I write the unix timestamp to the url of the browser. Of course I’m using date.getTime() in Flex.


Applying getTime() to any object of type Date in Flex results in a unix timestamp with included milliseconds. Of course the server side technology which in our case is PHP should devide by 1000 to remove the milliseconds. Continue reading Flex 3 DateChooser UTC issue