function setCompareTab(layerName){
	//hide all layers
	hideDiv('GeneralLayer');
	hideDiv('SpecsLayer');
	hideDiv('OptionsLayer');
	hideDiv('OtherLayer');
	//show selected layer
	showDiv(layerName);
	
	//hide all tabs
	MM_swapImage('GeneralTab','','images/compare/tabs/GeneralOff.jpg');
	MM_swapImage('SpecsTrans','','images/compare/tabs/curveOff.jpg');
	MM_swapImage('SpecsTab','','images/compare/tabs/SpecsOff.jpg');
	MM_swapImage('OptionTrans','','images/compare/tabs/curveOff.jpg');
	MM_swapImage('OptionsTab','','images/compare/tabs/OptionsOff.jpg');
	MM_swapImage('OtherTrans','','images/compare/tabs/curveOff.jpg');
	MM_swapImage('OtherTab','','images/compare/tabs/OtherOff.jpg');
	
	//set selected tab
	if(layerName == 'GeneralLayer'){
		MM_swapImage('GeneralTab','','images/compare/tabs/GeneralOn.jpg');
		MM_swapImage('OptionTrans','','images/compare/tabs/CurveOn.jpg');
	}
	if(layerName == 'OptionsLayer'){
		MM_swapImage('OptionTrans','','images/compare/tabs/LeftOn.jpg');
		MM_swapImage('OptionsTab','','images/compare/tabs/OptionsOn.jpg');
		MM_swapImage('SpecsTrans','','images/compare/tabs/CurveOn.jpg');
	}
	if(layerName == 'SpecsLayer'){
		MM_swapImage('SpecsTrans','','images/compare/tabs/LeftOn.jpg');
		MM_swapImage('SpecsTab','','images/compare/tabs/SpecsOn.jpg');
		MM_swapImage('OtherTrans','','images/compare/tabs/CurveOn.jpg');
	}
	if(layerName == 'OtherLayer'){
		MM_swapImage('OtherTrans','','images/compare/tabs/LeftOn.jpg');
		MM_swapImage('OtherTab','','images/compare/tabs/OtherOn.jpg');
	}
	
}

function hideDiv(divName){
    var div = document.getElementById(divName);
    div.style.display = 'none';
    div.style.visibility = 'hidden';
}

function showDiv(divName){
    var div = document.getElementById(divName);
    div.style.display = 'block';
    div.style.visibility = 'visible';
}