jQuery(document).ready(function(){
			
	if(jQuery("#buy_num").val()>0)
	{
	   count_go();
	}
	jQuery("#count").click(function(){
		count_go();
	});
	
	
  document.onkeydown = function(e){ 	
		if (e == null) { // ie
				keycode = event.keyCode;
			} else { // mozilla
				keycode = e.which;
			}
		if(keycode == 13){
			 count_go(); 
			 return false;
		} 	
	};

});//end ready

function count_go()
{
	//alert(jQuery("#basic_m").html());
		if (!IsInteger(jQuery("#buy_num").val(),' '))
		{
			alert('Error: Your must input a positive integer number'); 
		}
		else
		{
			var discount = 1;
			var standard_m = 29;
			var standard_y = 290;
			var video_m = 49;
			var video_y = 490;
			var standard_save,video_save;
		
			if(jQuery("#buy_num").val()>2 && jQuery("#buy_num").val() <11)
			{
				discount = 0.9;
			}
			else if(jQuery("#buy_num").val()>10 && jQuery("#buy_num").val() <25)
			{
				discount = 0.85;
			}
			else if( jQuery("#buy_num").val() > 24)
			{
				discount = 0.8;
			}
			

			var standard_m_old = standard_m;
			standard_m = parseInt(standard_m*discount*jQuery("#buy_num").val());
			//standard_y = parseInt(standard_y*discount*jQuery("#buy_num").val());
			standard_y = standard_m *10;
			jQuery("#standard_m").hide("slow");
			jQuery("#standard_y").hide("slow");
		    jQuery("#standard_m").replaceWith("<font id='standard_m'>"+standard_m+"</font>");
			jQuery("#standard_y").replaceWith("<font id='standard_y'>"+standard_y+"</font>");

			
			var video_m_old = video_m;
			video_m = parseInt(video_m*discount*jQuery("#buy_num").val());
			//video_y = parseInt(video_y*discount*jQuery("#buy_num").val());
			video_y =  video_m*10;
			jQuery("#video_m").hide("slow");
			jQuery("#video_y").hide("slow");
		    jQuery("#video_m").replaceWith("<font id='video_m'>"+video_m+"</font>");
			jQuery("#video_y").replaceWith("<font id='video_y'>"+video_y+"</font>");
			
			
				
		}
	
}

function IsInteger(string ,sign)
{ 
var integer;
	if ((sign!=null) && (sign!='-') && (sign!=' '))
	{
		alert('IsInter(string,sign)parameter error: sign should be null or "-" or " "');
		return false;
	}
integer = parseInt(string);
if (isNaN(integer))
{
	return false;
}
else if (integer.toString().length==string.length)
{
	if ((sign==null) || (sign=='-' && integer<0) || (sign==' ' && integer>0))
	{
		return true;
	}
	else
		return false;
}
else
	return false;
 
}