How To Change A Unix Timestamp In The Future To Seconds Remaining - php

I am trying to create a javascript countdown timer;
I have a string that is in the format of YYYY-MM-DD HH:MM:SS .
This could be any time up to 6 months in the future.
What would be the best way to go about getting the time remaining in seconds from now until the future time. This could be implemented in PHP.
Thanks in advance!

In PHP you can use strtotime, which takes a string representation of a date and returns the unix timestamp.
Then use microtime to get the current unix timestamp, and find the difference. This will be the number of milliseconds remaining, so divide it by 1000 to get it in seconds.
http://php.net/manual/en/function.strtotime.php
http://php.net/manual/en/function.microtime.php
This should work:
$currentTime = explode(" ", microtime());
$currentTime = $currentTime[1];
$futureTime = strtotime("YYYY-MM-DD HH:MM:SS"); // insert your date here
$timeRemaining = ($futureTime - $currentTime) / 1000;

How are you getting this string-based timestamp? A unix timestamp is actually already "number of seconds since 1970-01-01 00:00:00". That looks like a native MySQL date string.
If it is coming out of MySQL, you can convert it to a unix-style timestamp with UNIX_TIMESTAMP(), e.g.
SELECT unix_timestamp(datetimefield) ...
and then convert it to a Javascript timestamp by multiplying by 1000 (JS timestamps have the same epoch, but in milliseconds).
If you're stuck in PHP, you can go quick/dirt with
$timestamp = strtotime($time_string);
$js_timestamp = $timestamp * 1000;

Related

Check elapsed time in PHP from a MySQL datetime

How can I check how many seconds past the current time to a time in my MySQL database?
Example: The current time right now is 2018-07-21 10:04:20, and the time in my database is 2018-07-20 21:58:40.
I want to get how many seconds past the datetime in my database to the current date time.
You can use the strtotime() to convert your Date-Time to Unixtime an time() to get actual Timestamp:
$timestamp = strtotime("2018-07-21 10:04:20"); //replace with your DB-date
$diff = time() - $timestamp ; //calculate the Difference
echo $diff; //negative number is in the future
Just turn the date into number using strtotime.
$seconds = abs(strtotime($currentDate) - strtotime($dbDate));
I put abs in case of the result is negative.
strtotime returns the difference in seconds between 01-01-1970 and the date in parameter.

Negating one time from another

Hey guys i'm trying to figure out how to subtract one time from another using php to get the amount of time left between the two times. So for example
time left = time1-time2
or
timeleft = 15:35-15:30
which would be equal to 5mins left.
Currently I am loading the two times like so.
time1 is coming from my database (which is the time we are waiting for, and in my case the time we are waiting for is the time for next update) and time2 is the current system time.
I tried using this code
$timeleft = $dbtime - $curtime;
$dbtime = time loaded from database.
$curtime = current system time.
But that just returns a 0.
Any help is appreciated thanks.
Use strtotime to turn the date string to unix timestamp.
$timeleft = strtotime($dbtime) - strtotime($curtime);
You have to convert both times into timestamp. One good function for that is the strtotime() http://php.net/manual/en/function.strtotime.php that try to convert a string into timestamp.
Then do your maths as you know and then just use the date() http://www.php.net/manual/en/function.date.php function to fomrat your time into anything you like
Use strtotime to convert strings to unix timestamps:
$timedifference = strtotime($dbtime) - strtotime($curtime); // or also
$timedifference = strtotime($dbtime) - time();
You negating one string from another - the result in 0 because (int)(string) = 0
Your must use like this
$dbtime = time();
// query
$timeleft = time() - $dbtime;
See also strtotime() function, if you date is parsed by it

Converting string into Date() in JavaScript

How do I convert this timestamp from php into a javascript Date() object?
This is how I grab the time:
$timestart = time();
and I parse this to a javascript function and I want to convert it into a JavaScript date object.
help, all this date stuff confuses me quite a bit.
thanks,
If val contains your PHP value which is
the current time measured in the number of seconds since the Unix Epoch
then you just need this:
var timestart = new Date(val * 1000);
JavaScript uses the same base time as UNIX systems (midnight on 01/01/1970) but measured in milliseconds rather than seconds.
Solution here :
Convert a Unix timestamp to time in JavaScript
Substring the parts of the timestamp you need to create the Date. Then initialise like so,
var d = new Date(year, month, date);
This is a cross browser implementation.

Compare timestamp to date

I need to compare a timestamp to a date. I would just like to compare the date portion without the time bit. I need to check whether a timestamp occurs on the day before yesterday i.e. today - 2.
Could you show me a snippet please? Thank you.
I've been reading through the PHP docs but couldn't find a very clean way of doing this. What I found was converting the timestamp to a date with a particular format and comparing it to a date which I get by doing a time delta to get the date before yesterday and converting it to a particular format. Messy.
You can arcieve this by using the function strtotime.
To round to a day I personaly like to edit the timestamp. This is a notations of seconds since epoch. One day is 86400 seconds, so if you do the following caculation:
$time = $time - ( $time % 86400 );
You can convert it back to a date again with the date function of PHP, for example:
$readableFormat = date( 'd-m-Y', $time );
There is also much on the internet about this topic.
you can use the strtotime function
<?php
$time = strtotime("5 june 2010");
$before = strtotime("-1 day",$time);
$after = strtotime("+1 day",$time);

Getting timezone for JavaScript and PHP all mixed up

I'm trying to synchronize the timezone between a PHP script and some JavaScript code.
I want a PHP function that returns a timestamp in UTC. Does gmmktime() do that?
On the JavaScript side, I have:
var real_date = new Date();
real_date -= real_date.getTimezoneOffset() * 60000;
real_date /= 1000;
Does this convert the timestamp to UTC?
PHP
Just time() will do what you want. If you want an arbitrary timestamp, instead of the current time, then gmmktime will do that, yes.
Returns the current time measured in
the number of seconds since the Unix
Epoch (January 1 1970 00:00:00 GMT).
http://www.php.net/manual/en/function.time.php
Javascript
You can use the .UTC() method of a Date object to get # of milliseconds in UTC. However, your current solution should also work, if you're starting with a timestamp.
You can use time()
For the Javascript question UTC

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