if ( document.images ) {
		main_on= new Image(124,30);
		main_on.src="../images/booklist_over.gif";  
		main_off= new Image(124,30);
		main_off.src="../images/booklist.gif";  

		auth_on= new Image(124,30);
		auth_on.src="../images/author_over.gif";  
		auth_off= new Image(124,30);
		auth_off.src="../images/author.gif";  

		titl_on= new Image(124,30);
		titl_on.src="../images/title_over.gif";  
		titl_off= new Image(124,30);
		titl_off.src="../images/title.gif";  

		subj_on= new Image(124,30);
		subj_on.src="../images/subject_over.gif";  
		subj_off= new Image(124,30);
		subj_off.src="../images/subject.gif";  
	}


function setHover(imageName) {
	if (document.images)
    {
    	imgOn=eval(imageName + "_on.src");
    	document[imageName].src= imgOn;
    }
}

function setNormal(imageName) {
	if (document.images)
    {
     	imgOff=eval(imageName + "_off.src");
    	document[imageName].src= imgOff;
    }
}

function writeNavBar() {
	var buttonStr = new String();

/* This only looks so awful because of the triple-nesting of quotes needed here. */

	buttonStr += '<table border="0" cellpadding="0" cellspacing="0">';
	buttonStr += '<tr>';
	buttonStr += '<td align="left" valign="top" width="125" height="30"><a href="../booklist.htm"> <img name="main" src="../images/booklist.gif" alt="Book list main page" onmouseover="setHover(';
	buttonStr += "'";
	buttonStr += 'main';
	buttonStr += "'";
	buttonStr += ')" onmouseout="setNormal(';
	buttonStr += "'";
	buttonStr += 'main';
	buttonStr += "'";
	buttonStr += ')"> </td>';
	buttonStr += '<td width="5"></td>';
	buttonStr += '<td align="left" valign="top" width="125" height="30"><a href="../author.htm"> <img name="auth" src="../images/author.gif" alt="Book list author index" onmouseover="setHover(';
	buttonStr += "'";
	buttonStr += 'auth';
	buttonStr += "'";
	buttonStr += ')" onmouseout="setNormal(';
	buttonStr += "'";
	buttonStr += 'auth';
	buttonStr += "'";
	buttonStr += ')"> </td>';
	buttonStr += '<td width="5"></td>';
	buttonStr += '<td align="left" valign="top" width="125" height="30"><a href="../title.htm"> <img name="titl" src="../images/title.gif" alt="Book list title index" onmouseover="setHover(';
	buttonStr += "'";
	buttonStr += 'titl';
	buttonStr += "'";
	buttonStr += ')" onmouseout="setNormal(';
	buttonStr += "'";
	buttonStr += 'titl';
	buttonStr += "'";
	buttonStr += ')"> </td>';
	buttonStr += '<td width="5"></td>';
	buttonStr += '<td align="left" valign="top" width="125" height="30"><a href="../subject.htm"> <img name="subj" src="../images/subject.gif" alt="Book list subject index" onmouseover="setHover(';
	buttonStr += "'";
	buttonStr += 'subj';
	buttonStr += "'";
	buttonStr += ')" onmouseout="setNormal(';
	buttonStr += "'";
	buttonStr += 'subj';
	buttonStr += "'";
	buttonStr += ')"> </td>';
	buttonStr += '</tr>';
	buttonStr += '</table>';
	document.write( buttonStr );
}