Simple and practical countdown Effect of JS

I did not study the countdown effect, so I practiced it myself.

 <!  Doctype html  >  <  Html  >  <  Head  >  <  Meta  Charset  = "UTF-8"  >  <  Title  > Countdown </  Title  >  <  Meta  Name  = "Author"  Content  = ""  >  <  Meta  Name  = "Keywords"  Content  = ""  > <  Meta  Name  = "Description"  Content  = ""  >  <  Style  Type  = "Text/CSS"  >  *  {  Margin :  0  ;  Padding  :  0  ;      }  Ul, Li  {  List-style  : None  ;  }  # Show_time  {  Color  :  # F00  ;  Font-size  :  24px ;  Font-weight  :  Bold  ;  }  </  Style  >  </  Head  >  <  Body  > <  Div  ID  = "Show_time"  >  </  Div  >  <  Script  Type  = "Text/JavaScript"  >   Function  Countdown (){ VaR  Show_time  =  Document. getelementbyid (  "  Show_time  "  ); Endtime  =   New  Date ( "  12/31/2012 23:59:59  "  );  //  End Time  Today  =   New  Date ();  //  Current Time Delta_t  =  Endtime. gettime ()  -  Today. gettime ();  //  Interval      If  (Delta_t  <   0 ) {Clearinterval (auto); show_time.innerhtml  =   "  Countdown has ended  "  ;} Window. setTimeout (countdown,  1000  ); Total_days  =  Delta_t  / (24*60*60*1000 );  //  Total days  Total_show  =  Math. Floor (total_days );  //  Actual Number of days displayed  Total_hours  =  (Total_days -  Total_show)  *  24  ;  //  Remaining hours  Hours_show  =  Math. Floor (total_hours );  // Actual displayed hours  Total_minutes  =  (Total_hours  -  Hours_show)  *  60  ;  //  Remaining minutes Minutes_show  =  Math. Floor (total_minutes );  //  Actually displayed minutes  Total_seconds  =  (Total_minutes  -  Minutes_show)  * 60  ;  //  Remaining minutes  Seconds_show  =  Math. Floor (total_seconds );  //  Number of seconds actually displayed  Show_time.innerhtml  =  "  There are also:  "   +  Total_show  +   "  Days  "   +  Hours_show  +  "  Hour  "   +  Minutes_show  +   "  Minute  "   +  Seconds_show  +  "  Seconds  "  ;} Countdown ();  </  Script  >  </  Body  >  </  Html  >