Buenos dias!!
Estoy haciendo una página web que necesita un calendario, y me he descargado uno muy chulo. Le he hecho algunas modificaciones, pero lo que no consigo es que, al poner el raton sobre un día, le cambie el color del fondo. 
¿Alguien me puede ayudar? Adjunto la parte central del código 
Gracias!!
 
var	monthName =	new	Array("Enero","Febrero","Marzo","Abril","Mayo","Ju  nio","Julio","Agosto","Septiembre","Octubre","Novi  embre","Diciembre")
	var	monthName2 = new Array("ENE","FEB","MAR","ABR","MAY","JUN","JUL","A  GO","SEP","OCT","NOV","DIC")
	if (startAt==0)
	{
		dayName = new Array	("Lun","Mar","Mie","Jue","Vie","Sab","Dom")
	}
	else
	{
		dayName = new Array	("Lun","Mar","Mie","Jue","Vie","Sab","Dom")
	}
	var	styleAnchor="text-decoration:none;color:black;"
	var	styleLightBorder="border-style:solid;border-width:1px;border-color:#a0a0a0;"
 
	function swapImage(srcImg, destImg){
		if (ie)	{ document.getElementById(srcImg).setAttribute("src"  ,imgDir + destImg) }
	}
 
	function init()	{
		if (!ns4)
		{
			if (!ie) { yearNow += 1900	}
 
			crossobj=(dom)?document.getElementById("calendar")  .style : ie? document.all.calendar : document.calendar
			hideCalendar()
 
			crossMonthObj=(dom)?document.getElementById("selec  tMonth").style : ie? document.all.selectMonth	: document.selectMonth
 
			crossYearObj=(dom)?document.getElementById("select  Year").style : ie? document.all.selectYear : document.selectYear
 
			monthConstructed=false;
			yearConstructed=false;
 
			if (showToday==1)
			{
				document.getElementById("lblToday").innerHTML =	todayString + " <a onmousemove='window.status=\""+gotoString+"\"' onmouseout='window.status=\"\"' title='"+gotoString+"' style='"+styleAnchor+"' href='javascript:monthSelected=monthNow;yearSelect  ed=yearNow;constructCalendar();'>"+dayName[(today.getDay()-startAt==-1)?6:(today.getDay()-startAt)]+", " + dateNow + " " + monthName[monthNow].substring(0,15)	+ " de " +	yearNow	+ "</a>"
			}
 
			sHTML1="<span id='spanLeft'	style='border-style:solid;border-width:1;border-color:#ffffff;cursor:pointer' title='"+scrollLeftMessage+"' onmouseover='swapImage(\"changeLeft\",\"left2.gif\  ");this.style.borderColor=\"#88AAFF\";window.statu  s=\""+scrollLeftMessage+"\"' onclick='javascript:decMonth()' onmouseout='clearInterval(intervalID1);swapImage(\  "changeLeft\",\"left1.gif\");this.style.borderColo  r=\"#ffffff\";window.status=\"\"' onmousedown='clearTimeout(timeoutID1);timeoutID1=s  etTimeout(\"StartDecMonth()\",500)'	onmouseup='clearTimeout(timeoutID1);clearInterval(  intervalID1)'> <IMG id='changeLeft' SRC='"+imgDir+"left1.gif' width=10 height=11 BORDER=0> </span> "
			sHTML1+="<span id='spanRight' style='border-style:solid;border-width:1;border-color:#ffffff;cursor:pointer'	title='"+scrollRightMessage+"' onmouseover='swapImage(\"changeRight\",\"right2.gi  f\");this.style.borderColor=\"#88AAFF\";window.sta  tus=\""+scrollRightMessage+"\"' onmouseout='clearInterval(intervalID1);swapImage(\  "changeRight\",\"right1.gif\");this.style.borderCo  lor=\"#ffffff\";window.status=\"\"' onclick='incMonth()' onmousedown='clearTimeout(timeoutID1);timeoutID1=s  etTimeout(\"StartIncMonth()\",500)'	onmouseup='clearTimeout(timeoutID1);clearInterval(  intervalID1)'> <IMG id='changeRight' SRC='"+imgDir+"right1.gif'	width=10 height=11 BORDER=0> </span> "
			sHTML1+="<span id='spanMonth' style='border-style:solid;border-width:1;border-color:#ffffff;cursor:pointer'	title='"+selectMonthMessage+"' onmouseover='swapImage(\"changeMonth\",\"drop2.gif  \");this.style.borderColor=\"#88AAFF\";window.stat  us=\""+selectMonthMessage+"\"' onmouseout='swapImage(\"changeMonth\",\"drop1.gif\  ");this.style.borderColor=\"#ffffff\";window.statu  s=\"\"' onclick='popUpMonth()'></span> "
			sHTML1+="<span id='spanYear' style='border-style:solid;border-width:1;border-color:#fffffff;cursor:pointer' title='"+selectYearMessage+"' onmouseover='swapImage(\"changeYear\",\"drop2.gif\  ");this.style.borderColor=\"#88AAFF\";window.statu  s=\""+selectYearMessage+"\"'	onmouseout='swapImage(\"changeYear\",\"drop1.gif\"  );this.style.borderColor=\"#ffffff\";window.status  =\"\"'	onclick='popUpYear()'></span> "
 
			document.getElementById("caption").innerHTML  =	sHTML1
 
			bPageLoaded=true
		}
	}
 
	function hideCalendar()	{
		crossobj.visibility="hidden"
		if (crossMonthObj != null){crossMonthObj.visibility="hidden"}
		if (crossYearObj !=	null){crossYearObj.visibility="hidden"}
 
	    showElement( 'SELECT' );
		showElement( 'APPLET' );
	}
 
	function padZero(num) {
		return (num	< 10)? '0' + num : num ;
	}
 
	function constructDate(d,m,y)
	{
		sTmp = dateFormat
		sTmp = sTmp.replace	("dd","<e>")
		sTmp = sTmp.replace	("d","<d>")
		sTmp = sTmp.replace	("<e>",padZero(d))
		sTmp = sTmp.replace	("<d>",d)
		sTmp = sTmp.replace	("mmmm","<p>")
		sTmp = sTmp.replace	("mmm","<o>")
		sTmp = sTmp.replace	("mm","<n>")
		sTmp = sTmp.replace	("m","<m>")
		sTmp = sTmp.replace	("<m>",m+1)
		sTmp = sTmp.replace	("<n>",padZero(m+1))
		sTmp = sTmp.replace	("<o>",monthName[m])
		sTmp = sTmp.replace	("<p>",monthName2[m])
		sTmp = sTmp.replace	("yyyy",y)
		return sTmp.replace ("yy",padZero(y%100))
	}
function constructMonth() {
		popDownYear()
		if (!monthConstructed) {
			sHTML =	""
			for	(i=0; i<12;	i++) {
				sName =	monthName[i];
				if (i==monthSelected){
					sName =	"<B>" +	sName +	"</B>"
				}
				sHTML += "<tr><td id='m" + i + "' onmouseover='this.style.backgroundColor=\"#FFCC99\  "' onmouseout='this.style.backgroundColor=\"\"' style='cursor:pointer' onclick='monthConstructed=false;monthSelected=" + i + ";constructCalendar();popDownMonth();event.cancelB  ubble=true'> " + sName + " </td></tr>"
			}
 
			document.getElementById("selectMonth").innerHTML = "<table width=70	style='font-family:arial; font-size:11px; border-width:1; border-style:solid; border-color:#a0a0a0;' bgcolor='#FFFFDD' cellspacing=0 onmouseover='clearTimeout(timeoutID1)'	onmouseout='clearTimeout(timeoutID1);timeoutID1=se  tTimeout(\"popDownMonth()\",100);event.cancelBubbl  e=true'>" +	sHTML +	"</table>"
 
			monthConstructed=true
		}
	}
function constructCalendar () {
		var aNumDays = Array (31,0,31,30,31,30,31,31,30,31,30,31)
 
		var dateMessage
		var	startDate =	new	Date (yearSelected,monthSelected,1)
		var endDate
 
		if (monthSelected==1)
		{
			endDate	= new Date (yearSelected,monthSelected+1,1);
			endDate	= new Date (endDate	- (24*60*60*1000));
			numDaysInMonth = endDate.getDate()
		}
		else
		{
			numDaysInMonth = aNumDays[monthSelected];
		}
 
		datePointer	= 0
		dayPointer = startDate.getDay() - startAt
 
		if (dayPointer<0)
		{
			dayPointer = 6
		}
 
		sHTML =	"<table	 border=0 style='font-family:verdana;font-size:10px;'><tr>"
 
 
 
		for	(i=0; i<7; i++)	{
			sHTML += "<td width='27' align='right'><B>"+ dayName[i]+"</B></td>"
		}
		sHTML +="</tr><tr>"
 
 
 
		for	( var i=1; i<=dayPointer;i++ )
		{
			sHTML += "<td> </td>"
		}
 
		for	( datePointer=1; datePointer<=numDaysInMonth; datePointer++ )
		{
			dayPointer++;
			sHTML += "<td align=right>"
			sStyle=styleAnchor
			if ((datePointer==odateSelected) &&	(monthSelected==omonthSelected)	&& (yearSelected==oyearSelected))
			{ sStyle+=styleLightBorder }
 
			sHint = ""
			for (k=0;k<HolidaysCounter;k++)
			{
				if ((parseInt(Holidays[k].d)==datePointer)&&(parseInt(Holidays[k].m)==(monthSelected+1)))
				{
					if ((parseInt(Holidays[k].y)==0)||((parseInt(Holidays[k].y)==yearSelected)&&(parseInt(Holidays[k].y)!=0)))
					{
						sStyle+="background-color:#FFDDDD;"
						sHint+=sHint==""?Holidays[k].desc:"\n"+Holidays[k].desc
					}
				}
			}
 
			var regexp= /\"/g
			sHint=sHint.replace(regexp,""")
 
			dateMessage = "onmousemove='window.status=\""+selectDateMessage.  replace("[date]",constructDate(datePointer,monthSelected,yearSele  cted))+"\";' onmouseout='window.status=\"\"' "
 
			var f1= new Date(yearSelected,monthSelected,datePointer);
//------------------------------------TERMINAR LA FUNCION EN 0 PARA QUE INICIE EN EL DIA ACTUAL EN LA SIGUIENTE LINEA----------------------------------------------
			var temp = addToDate(makeDateFormat(dateNow, monthNow, yearNow),0);
			var nDia = Number(temp.substr(0, 2)); 
   			var nMes = Number(temp.substr(3, 2)); 
   			var nAno = Number(temp.substr(6, 4)); 
			var fa= new Date(nAno,nMes,nDia);
 
			if ((datePointer==nDia)&&(monthSelected==nMes)&&(year  Selected==nAno))
			//{ sHTML += "<b style='"+sStyle+"'><font color=#ff0000> " + datePointer + "</font> </b>"}
			{ sHTML += "<b><a "+dateMessage+" title=\"" + sHint + "\" style='"+sStyle+"' href='javascript:dateSelected="+datePointer+";clos  eCalendar();' ><font color=#ff0000> " + datePointer + "</font> </a></b>"}
			//else if	(dayPointer % 7 == (startAt * -1)+1)
			//{ sHTML += "<a "+dateMessage+" title=\"" + sHint + "\" style='"+sStyle+"' href='javascript:dateSelected="+datePointer + ";closeCalendar();'> <font color=#909090>" + datePointer + "</font> </a>" }
			else if (FechaMenor(fa,f1)) //((datePointer<dateNow)&&(monthSelected<=monthNow)&  &(yearSelected=yearNow))
			{ sHTML += " <font color=#909090>" + datePointer + "</font> " }
			else
			{ sHTML += "<a "+dateMessage+" title=\"" + sHint + "\" style='"+sStyle+"' href='javascript:dateSelected="+datePointer + ";closeCalendar();'> " + datePointer + " </a>" }
 
			sHTML += ""
			if ((dayPointer+startAt) % 7 == startAt) { 
				sHTML += "</tr><tr>" 
 
			}
		}
 
		document.getElementById("content").innerHTML   = sHTML
		document.getElementById("spanMonth").innerHTML = " " +	monthName[monthSelected] + " <IMG id='changeMonth' SRC='"+imgDir+"drop1.gif' WIDTH='12' HEIGHT='10' BORDER=0>"
		document.getElementById("spanYear").innerHTML =	" " + yearSelected	+ " <IMG id='changeYear' SRC='"+imgDir+"drop1.gif' WIDTH='12' HEIGHT='10' BORDER=0>"
	} 
  
 
