function getRandomHeaderCSS()
{
	
	var numberOfCSSFile = 2;
	var randomFile=Math.floor(Math.random()*numberOfCSSFile);
 
    var randomHeaderCSS=new Array(numberOfCSSFile)

	cssName[0]="<link rel='stylesheet' type='text/css' href='../custom_style/header.css'>";
	cssName[1]="<link rel='stylesheet' type='text/css' href='../custom_style/header.css'>";
	
	alert(randomFile);
  	return randomHeaderCSS[randomFile]
}
document.write(getRandomHeaderCSS());
alert('2');