var taille = 12;
var tailleCss = null;
function upSize(className)
{
	if(taille + 2 < 20)
	{
		taille += 2;
		mod_zoom_updateCssSize(className);
	}
}
function downSize(className)
{
	if(taille - 2 > 8)
	{
		taille -= 2;
		mod_zoom_updateCssSize(className);
	}
}
function mod_zoom_updateCssSize(className)
{
	if( tailleCss == null)
		tailleCss = getCssRule(className);
	tailleCss.style.fontSize=taille+'px';
} 

function getCssRule(className)
{
	for (var sSheet=0; sSheet < document.styleSheets.length; sSheet++){
		if(document.styleSheets[sSheet].cssRules == undefined)
		{
			for (var rule=0; rule < document.styleSheets[sSheet].rules.length; rule++) {
			var currentClass = document.styleSheets[sSheet].rules[rule].selectorText.substring(1);
			if (currentClass == className) {
			  return document.styleSheets[sSheet].rules[rule];
			}
		  }
		}
		else
		{
		  for (var rule=0; rule < document.styleSheets[sSheet].cssRules.length; rule++) {
			var currentClass = document.styleSheets[sSheet].cssRules[rule].selectorText.substring(1);
			if (currentClass == className) {
			  return document.styleSheets[sSheet].cssRules[rule];
			}
		  }
	  }
	}
}