[Nichol]

Смотрите зделал так:

<script language="JavaScript">
function Count(form) {

	var TicketCount 		= document.getElementById('TicketCount');
	var TicketVipCount 		= document.getElementById('TicketVipCount');
	var TableCount	 		= document.getElementById('TableCount');

	var TicketPrice			= 40; 
	var TicketVipPrice		= 100; 
	var TablePrice			= 50;
	
	var MyCount				= 278;
	
 if (TicketPrice != '0') {
	var TicketExit			= parseFloat(TicketPrice) * TicketCount.value;
 }
 else {
	var TicketExit			= 0;
 }
	
if (TicketVipPrice != '0') {
	var TicketVipExit 		= parseFloat(TicketVipPrice) * TicketVipCount.value;
 }
 else {
	var TicketVipExit 		= 0;
 }
 
 if (TablePrice != '0') {
	var TableExit 			= parseFloat(TablePrice) * TableCount.value;
 }
 else {
	var TableExit	 		= 0;
 }
	
	var SumPrice = TicketExit + TicketVipExit + TableExit;

 if (SumPrice >= MyCount) {
    document.getElementById('but').disabled = true;
	var NeedToPay = SumPrice - MyCount;
	document.getElementById('debug').innerHTML = 'ERROR :) '+ NeedToPay +' ';
	document.getElementById('sum').innerHTML = '';
 }
 else {
    document.getElementById('but').disabled = false;
	document.getElementById('debug').innerHTML = '';
	document.getElementById('sum').innerHTML = SumPrice.toFixed(2);
 }
 
}
</script>

<form method="POST">
	<table border="0" cellspacing="4" cellpadding="3">
		<tr><td style="color: #3A7611; vertical-align: middle; width: 300px">Кількість квитків:</td><td><select id="TicketCount" onChange="Count(this)" name="TicketCount" size="1" style="width: 50px"><option>0</option><option>1</option><option>2</option><option>3</option><option>4</option><option>5</option><option>6</option><option>7</option><option>8</option><option>9</option><option>10</option><option>11</option><option>12</option><option>13</option><option>14</option><option>15</option><option>16</option><option>17</option><option>18</option><option>19</option><option>20</option></select></td></tr>

		<tr><td style="color: #3A7611; vertical-align: middle">Кількість VIP квитків:</td><td><select id="TicketVipCount" onChange="Count(this)" name="TicketVipCount" size="1" style="width: 50px"><option>0</option><option>1</option><option>2</option></select></td></tr>
		<tr><td style="color: #3A7611; vertical-align: middle">Кількість столиків:</td><td><select id="TableCount" onChange="Count(this)" name="TableCount" size="1" style="width: 50px"><option>0</option><option>1</option><option>2</option><option>3</option><option>4</option><option>5</option><option>6</option><option>7</option><option>8</option><option>9</option><option>10</option><option>11</option><option>12</option></select></td></tr>

	</table>

<input type="submit" id="but" value="увійти" class="buttom_small">
</form>

все вроде нормально, пашет всюда кроме IE. исправте пожалуйста!!!