function randomFactor()
{
number = Math.floor(Math.random()*4)
if (number==0)
document.write('<div id="mainContentHome1">')
if (number==1)
document.write('<div id="mainContentHome2">')
if (number==2)
document.write('<div id="mainContentHome3">')
if (number==3)
document.write('<div id="mainContentHome4">')

}