Script code function

Question

Could someone explain to me what the part that says means in this code:

document.cookie = 'useHTML5=; expires=Thu, 01 Jan 1970 00:00:01

It appears more than once, I wonder if it is something related to a valid script date, and why the year 1970

In the script also has some encoded links, I decrypted some and in all of them appears the part (expire)

https://redirector.googlevideo.com/videoplayback?requiressl=yes&shardbypass=yes&cmbypass=yes&id=a65e10712772b860&itag=37&source=picasa&cmo=secure_transport=yes&ip=0.0.0.0&ipbits=0expire=0expire=1410146288&sparams=requiressl,shardbypass,bypass,id,itag,source,ip,ipipbits,expire&signature=520E18C71BF843019359E7EB492F8CBD928385BD.35D96C19784732AC04B057DC838BC70B21E467D7&key=lh1

Already on that other link the part that refers expire is different

http://redirector.googlevideo.com/videoplayback?id=d4f4531d811f6fc8&itag=18&source=picasa&cmo=sensitive_content=yes&ip=0.0.0&ipbits=0expire&=1407845352&sparams=id,itag source,,,ip,ipbits,expire&signature=CBB7533D638BE53685D14770144A4808C129B264.275AA97CABC08AB6AD4BC8780EC905DCA9989D9A&key=lh1

This script would have the function of changing that date or something like that?

<script type="text/javascript">
        $(document).ready(function () {
            $("#divContentVideo").allofthelights({
                'opacity': '0.95',
                'clickable_bg': 'true',
                'callback_turn_off': function() {
                    $('.allofthelights_bg').hide().show(0);
                    $('#switch').hide();
                },
                'callback_turn_on': function() {
                    $('#switch').show();
                }
            });


            setTimeout('ReloadIfNeed()', 10000);

        });

        function ReloadIfNeed(){
            if ($('#divFileName').html().indexOf("My Movie") > 0)
            {
                location.reload();
            }
        }


        var isHTML5 = false;
        if (document.cookie.indexOf("useHTML5") >= 0) {
            isHTML5 = true;
            $('#playerChoose').html('-> Switch to Flash Player (more stable & better quality)');
            $('#qualityChoose').show();
        }

        var isHTML5HQ = false;
        if (document.cookie.indexOf("isHTML5HQ") >= 0) {
            isHTML5HQ = true;
            $('#qualityChoose').html('-> Switch to HTML5 LOW quality');
        }

        $('#playerChoose').click(function () {
            if (isHTML5)
            {
                document.cookie = 'useHTML5=; expires=Thu, 01 Jan 1970 00:00:01 GMT;path=/';
                document.cookie = 'useFlash=true;path=/';
            }
            else
            {
                document.cookie = 'useHTML5=true;path=/';
                document.cookie = 'useFlash=; expires=Thu, 01 Jan 1970 00:00:01 GMT;path=/';
            }

            document.location.reload(true);
        });

        $('#qualityChoose').click(function () {
            if (isHTML5HQ)
            {
                document.cookie = 'isHTML5HQ=; expires=Thu, 01 Jan 1970 00:00:01 GMT;path=/';
                document.cookie = 'isHTML5LQ=true;path=/';
            }
            else
            {
                document.cookie = 'isHTML5HQ=true;path=/';
                document.cookie = 'isHTML5LQ=; expires=Thu, 01 Jan 1970 00:00:01 GMT;path=/';
            }

            document.location.reload(true);
        });

        var txha = 'fmt_list=37%2F1920x1080%2C22%2F1280x720%2C35%2F854x480%2C34%2F640x360%2C18%2F640x360&amp;fmt_stream_map=37%7Chttps%3a%2f%2fredirector.googlevideo.com%2fvideoplayback%3frequiressl%3dyes%26shardbypass%3dyes%26cmbypass%3dyes%26id%3da65e10712772b860%26itag%3d37%26source%3dpicasa%26cmo%3dsecure_transport%3dyes%26ip%3d0.0.0.0%26ipbits%3d0%26expire%3d1410146288%26sparams%3drequiressl%252Cshardbypass%252Ccmbypass%252Cid%252Citag%252Csource%252Cip%252Cipbits%252Cexpire%26signature%3d520E18C71BF843019359E7EB492F8CBD928385BD.35D96C19784732AC04B057DC838BC70B21E467D7%26key%3dlh1%2C22%7Chttps%3a%2f%2fredirector.googlevideo.com%2fvideoplayback%3frequiressl%3dyes%26shardbypass%3dyes%26cmbypass%3dyes%26id%3da65e10712772b860%26itag%3d22%26source%3dpicasa%26cmo%3dsecure_transport%3dyes%26ip%3d0.0.0.0%26ipbits%3d0%26expire%3d1410146288%26sparams%3drequiressl%252Cshardbypass%252Ccmbypass%252Cid%252Citag%252Csource%252Cip%252Cipbits%252Cexpire%26signature%3d11DBC00A15B49979B0B9A23004174EF4FFF7A925.32E74A92AEE34FADEC0096642702584FD658DBBF%26key%3dlh1%2C35%7Chttps%3a%2f%2fredirector.googlevideo.com%2fvideoplayback%3frequiressl%3dyes%26shardbypass%3dyes%26cmbypass%3dyes%26id%3da65e10712772b860%26itag%3d35%26source%3dpicasa%26cmo%3dsecure_transport%3dyes%26ip%3d0.0.0.0%26ipbits%3d0%26expire%3d1410146288%26sparams%3drequiressl%252Cshardbypass%252Ccmbypass%252Cid%252Citag%252Csource%252Cip%252Cipbits%252Cexpire%26signature%3dABE28CFF2DF9768DDCBEBC525145903668D9A9F6.CC31D9AC79E0EF78E20C88DDCEC6D1B537E68268%26key%3dlh1%2C34%7Chttps%3a%2f%2fredirector.googlevideo.com%2fvideoplayback%3frequiressl%3dyes%26shardbypass%3dyes%26cmbypass%3dyes%26id%3da65e10712772b860%26itag%3d34%26source%3dpicasa%26cmo%3dsecure_transport%3dyes%26ip%3d0.0.0.0%26ipbits%3d0%26expire%3d1410146288%26sparams%3drequiressl%252Cshardbypass%252Ccmbypass%252Cid%252Citag%252Csource%252Cip%252Cipbits%252Cexpire%26signature%3d700BCAB38FAB60AD6AABC3549B9E7C74D3ED489C.57F7DC1FC5A065786DB4F2E6277D1546D54ACF2B%26key%3dlh1%2C18%7Chttps%3a%2f%2fredirector.googlevideo.com%2fvideoplayback%3frequiressl%3dyes%26shardbypass%3dyes%26cmbypass%3dyes%26id%3da65e10712772b860%26itag%3d18%26source%3dpicasa%26cmo%3dsecure_transport%3dyes%26ip%3d0.0.0.0%26ipbits%3d0%26expire%3d1410146288%26sparams%3drequiressl%252Cshardbypass%252Ccmbypass%252Cid%252Citag%252Csource%252Cip%252Cipbits%252Cexpire%26signature%3d270F5022125B383BF7365840657C61CB83505AA5.97F4F9604EEDEBE76CC22625C2F8AAE4761D0970%26key%3dlh1&amp;video_id=picasacid&amp;fs=1&amp;hl=en&amp;autoplay=1&amp;ps=picasaweb&amp;playerapiid=uniquePlayerId&amp;t=1&amp;vq=large&amp;auth_timeout=86400000000';


        $('#selectEpisode').change(function () {
            location.href = 'http://kissanime.com/Anime/K-On-2-Dub/' + $(this).val();
        });

        $('#selectGroup').change(function () {
            location.href = 'http://kissanime.com/Anime/' + $(this).val();
        });


        if (isHTML5) {
            $('#divContentVideo').html('<video id="my_video_1" class="video-js vjs-default-skin" controls autoplay preload="auto" width="854px" height="552px" data-setup="{}"><source src="' + txha + '" type="video/mp4"></video>');            
            //$('#divContentVideo').html('<div style="position: relative;width:100%;height:100%"><div data-swf="//releases.flowplayer.org/5.4.3/flowplayer.swf" class="flowplayer play-button" style="position: absolute; bottom: 0;" data-embed="false"><video preload="auto" autoplay><source type="video/mp4" src="' + txha + '"/></video></div></div>');
            $('#divTextQua').html('IF THE PLAYER DOES NOT WORK, PLEASE CLICK ON THE URLS BELOW TO WATCH VIDEO');            


                $('#switch').css('left', '860px');
                $('#switch').css('top', '530px');

        }
        else
        {
            //$('#divContentVideo').show();
            setTimeout('DoHideFake()', 2000);
        }

        function DoHideFake()
        {
            $('#divContentVideo').append('<embed id="embedVideo" height="552" src="//www.youtube.com/get_player?enablejsapi=1&modestbranding=1"type="application/x-shockwave-flash" width="854" allowfullscreen="true" allowscriptaccess="always" bgcolor="#fff" scale="noScale" wmode="opaque" flashvars="' + txha + '" style="width: 854px; height: 552px" />');
        }


        function NextEps() {
            $('#divMsg').css('display', 'block');
        }



    </script>

Answer 1

In your code is removing the cookie, the date is to force the removal.

• useHTML5 = ''
• expires = Thu, 01 Jan 1970 00:00:01

That is to say, useHTML5 without an assigned value - null, and the date of the cookie already expired.
In this case the cookie is simply deleted.

_{Why set the date in 1970?}

The date Thu, 01 Jan 1970 00:00:01 ensures that the cookie is removed, even if the user’s computed date is not the current date. If the user changes the date of the PC, 1970 ensures the removal without conflict of date.

An example for cookie creation valid until the end of the year.

document.cookie="username=John Doe; expires=Thu, 18 Dec 2014 12:00:00 GMT";

_[reference]

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The googlevideo URL probably loads the player controls.