Ejemplos en Javascript

Efecto "flash" de colores al entrar

<HTML>
<HEAD>

<TITLE>Ejemplos Javascript: ejemplo pr???¡ctico </TITLE>

<script>

function initArray() {
  this.length = initArray.arguments.length
  for (var i = 0; i < this.length; i++)
    this[i+1] = initArray.arguments[i]
}

var hexChars = "0123456789ABCDEF";

function Dec2Hex (Dec) {
  var a = Dec % 16;
  var b = (Dec - a)/16;
  hex = "" + hexChars.charAt(b) + hexChars.charAt(a);
  return hex;
}

function bgChanger (begin, end, steps) {
  steps = steps -1 ;

  redA     = begin.charAt(0) + begin.charAt(1);
  red_valA = parseInt(redA,'16');
  redB     = end.charAt(0) + end.charAt(1);
  red_valB = parseInt(redB,'16');
  red_int  = ((red_valB - red_valA) / steps) * -1;
  grnA     = begin.charAt(2) + begin.charAt(3);
  grn_valA = parseInt(grnA,'16');
  grnB     = end.charAt(2) + end.charAt(3);
  grn_valB = parseInt(grnB,'16');
  grn_int  = ((grn_valB - grn_valA) / steps) * -1;
  bluA     = begin.charAt(4) + begin.charAt(5);
  blu_valA = parseInt(bluA,'16');
  bluB     = end.charAt(4) + end.charAt(5);
  blu_valB = parseInt(bluB,'16');
  blu_int  = ((blu_valB - blu_valA) / steps) * -1;

  step = 2;
  red = red_valA;
  grn = grn_valA;
  blu = blu_valA;

  document.bgColor = begin;

  while ( steps >= step ) {
    red -= red_int;
    red_round = Math.round(red);
    red_hex = Dec2Hex(red);

    grn -= grn_int;
    grn_round = Math.round(grn);
    grn_hex = Dec2Hex(grn);

    blu -= blu_int;
    blu_round = Math.round(blu);
    blu_hex = Dec2Hex(blu);

    document.bgColor = red_hex + grn_hex + blu_hex;
//    document.write("<br>bgcolor = " + red_hex + grn_hex + blu_hex);

    step++;
  }
  document.bgColor = end;
}

</script>

<script>
<!--
// nero a nero (pausa)
  bgChanger("000000","000000",25);
// nero a rosso
  bgChanger("000000","FF0000",25);
// rosso a nero
  bgChanger("FF0000","000000",25);
// rosso a viola
  bgChanger("000000","AA00EE",25);
// viola a nero
  bgChanger("AA00EE","000000",25);
// nero a blu
  bgChanger("000000","0000FF",25);
// blu a nero
  bgChanger("0000FF","000000",25);
// nero a nero (pausa)
  bgChanger("000000","000000",25);
// -->
</script>

</HEAD>

<BODY bgcolor="white">

 



</body>
</html>

Background y fondo