function abertura()
{

  var now = new Date();
  var seconds = now.getSeconds();
  if (seconds >=0 && seconds <=6)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm001.jpg)";
  else if(seconds >=7 && seconds <=12)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm002.jpg)";
  else if(seconds >=13 && seconds <=19)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm003.jpg)";
  else if(seconds >=20 && seconds <=25)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm004.jpg)";
  else if(seconds >=26 && seconds <=31)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm005.jpg)";
  else if(seconds >=32 && seconds <=37)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm006.jpg)";
  else if(seconds >=38 && seconds <=43)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm007.jpg)";
  else if(seconds >=49 && seconds <=54)
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm008.jpg)";
  else
    document.getElementById("benvindo").style.backgroundImage="url(images/img_tjm009.jpg)";
}