function contraste(){
   window.document.bgColor='black';
   var trgt='body';
/*
   document.getElementById('acessiblidade').style.color='red';
   document.getElementById('acessiblidade').style.fontWeight='bold';
   document.getElementById('acessiblidade2').style.color='red';
   document.getElementById('acessiblidade2').style.fontWeight='bold';
   document.getElementById('acessiblidade3').style.color='red';
   document.getElementById('acessiblidade3').style.fontWeight='bold';
   document.getElementById('acessiblidade4').style.color='red';
   document.getElementById('acessiblidade4').style.fontWeight='bold';
   document.getElementById('acessiblidade5').style.color='red';
   document.getElementById('acessiblidade5').style.fontWeight='bold';
   document.getElementById('titulo2').style.color='red';
   document.getElementById('titulo_texto').style.color='red';
   document.getElementById('texto').style.color='red';
   document.getElementById('tamanho').style.color='red';
*/

  //Specify affected tags. Add or remove from list:
  var tgs = new Array( 'div','span','td','a' );

  var d = document,cEl = null,sz = startSz,i,j,cTags;
  startSz = sz;
  if ( !( cEl = d.getElementById( trgt ) ) )
      cEl = d.getElementsByTagName( trgt )[ 0 ];
  cEl.style.color='red';


  for ( i = 0; i < tgs.length; i++ ) {
     cTags = cEl.getElementsByTagName( tgs[ i ] );
     for ( j = 0; j < cTags.length; j++ ){
       cTags[ j ].style.color='red';
       cTags[ j ].style.fontWeight='bold';
     }
  }
 window.parent.document.getElementById("iframe_corpo").height = document.getElementById("tamanho").scrollHeight + 140;

 }