var preloadFlag = false;
	if (document.images) {
		leftnav0off=new Image();leftnav0off.src="/GreatSource/images/leftnav/prof_dev_off.gif";
		leftnav0on=new Image();leftnav0on.src="/GreatSource/images/leftnav/prof_dev_on.gif";
		leftnav0in=new Image();leftnav0in.src="/GreatSource/images/leftnav/prof_dev_in.gif";
		leftnav1off=new Image();leftnav1off.src="/GreatSource/images/leftnav/research_efficacy_off.gif";
		leftnav1on=new Image();leftnav1on.src="/GreatSource/images/leftnav/research_efficacy_on.gif";
		leftnav1in=new Image();leftnav1in.src="/GreatSource/images/leftnav/research_efficacy_in.gif";
		leftnav2off=new Image();leftnav2off.src="/GreatSource/images/leftnav/grants_and_funding_off.gif";
		leftnav2on=new Image();leftnav2on.src="/GreatSource/images/leftnav/grants_and_funding_on.gif";
		leftnav2in=new Image();leftnav2in.src="/GreatSource/images/leftnav/grants_and_funding_in.gif";
		leftnav3off=new Image();leftnav3off.src="/GreatSource/images/leftnav/virtual_catalog_off.gif";
		leftnav3on=new Image();leftnav3on.src="/GreatSource/images/leftnav/virtual_catalog_on.gif";	
		//the following are not in use 
		leftnav4off=new Image();leftnav4off.src="/GreatSource/images/leftnav/il_textbook_off.gif";
		leftnav4on=new Image();leftnav4on.src="/GreatSource/images/leftnav/il_textbook_on.gif";		

		leftnav5off=new Image();leftnav5off.src="/GreatSource/images/leftnav/NY-educators_off.gif";
		leftnav5on=new Image();leftnav5on.src="/GreatSource/images/leftnav/NY-educators_on.gif";

		leftnav6off=new Image();leftnav6off.src="/GreatSource/images/leftnav/correlbut_off.gif";
		leftnav6on=new Image();leftnav6on.src="/GreatSource/images/leftnav/correlbut_on.gif";

preloadFlag = true;
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