Question

When I use pushState with http_build_query, it generates random number in query string.

For example:

example.com/?_=1356033912215&…

However, If I don’t use http_build_query, this parameter doesn’t show up. Also, each number starts with 13560…

What does this parameter mean?

Thanks in advance.

Answer 1

I could be wrong but I believe it is what is referred to as a cache buster. I have seen this before in my own code when you using jQuery’s $.ajax with the cache: false set.

jQuery generates a timestamp on the end of the query string to force the page to reload and pull the data from the server. It’s a way to fool browsers into reloading content that has been recently updated on the server side, but may have been cached on the client side.

It appears the http_build_query is performing a similar cache busting function.

In regards to the first few numbers, I venture a guess that the time stamp is most likely generated in seconds, so its not often that the front numbers would roll over if you catch what I’m saying. A million seconds is a long time, so you wouldn’t see a difference in the front numbers in a short amount of time.