如何将日期时间字符串转换为UTC？

Question

How can i convert a datetime string like this: 2012-09-03 22:00 US Estern to UTC timezone?

Answer 1

You should look at the DateTime object and its related functions in the documentation.

If your input date is already in a string format, DateTime::createFromFormat() will help you create an epoch-type integer date the object can work with. After that, it's just getTimezone() and setTimezone().

Answer 2

You could convert your timestamps from DB to epoch time with strtotime and wrap them in a special CSS class :

<span class="timestamp"><?php echo strtotime('2012-09-03 22:00'); ?></span>

And then with a bit of a Javascript (jQuery example), dynamically transform the unix epoch into a locale datetime :

    $('.timestamp').each(function(){
        var seconds = $(this).html();
        var d = new Date(1000 * parseInt(seconds));
        var t = (d.getMonth()<9 ? '0':'') + parseInt(d.getMonth()+1) + '/';
        t+= (d.getDate()<10 ? '0' : '') + parseInt(d.getDate()) + '/';  
        t+= parseInt((d.getYear()<1000 ? d.getYear()+1900 : d.getYear())) + ' ';
        t+= (d.getHours()<10 ? '0' : '') + d.getHours() + ':' + (d.getMinutes()<10 ? '0' : '') + d.getMinutes();            
        $(this).html(t);
    });  

This will output dates in the format mm/dd/yyyy hh:ii, relative to browser timezone.