//return -1 if field is negative, else returns the non-negative value

function getNonNegInteger(field)
{
	var ret=-1;
	var i=0;
	var ch='a';
	var value;
	
	if(field && field.length)
	{
		for (i=0; i < field.length; i++) 
		{
			ch = field.charAt(i);
			if(ch!='0' && ch!='1' && ch!='2' && ch!='3' && ch!='4' && ch!='5' && ch!='6' && ch!='7' && ch!='8' && ch!='9')
				break;
		}
		
		if(i==field.length)
		{
			value=parseInt(field);
			if(value>=0)
				ret=value;
		}
	}
	
	return ret;
}

function getNonNegFloat(field)
{
	var ret=-1.0;
	var i=0;
	var ch='a';
	var value;
	
	if(field && field.length)
	{
		for (i=0; i < field.length; i++) 
		{
			ch = field.charAt(i);
			if(ch!='.' && ch!='0' && ch!='1' && ch!='2' && ch!='3' && ch!='4' && ch!='5' && ch!='6' && ch!='7' && ch!='8' && ch!='9')
				break;
		}
		
		if(i==field.length)
		{
			value=parseFloat(field);
			if(value>=0)
				ret=value;
		}
	}
	
	return ret;
}



function makedirectoryname(padding_char, max_chars, id)
{
	dir_name="";
	for (i=0; i < max_chars-id.length; i++) 
		dir_name+=padding_char;
	dir_name+=id;
	return dir_name;
}

function showHideMessage(messageid)
{
	if(!messageid)
		return;
		
	var div_id="div_"+messageid;
	
	var div=document.getElementById(div_id);
	
	if(!div)
		return;
		
	if(div.style.display=='block')
		div.style.display='none';
	else
		div.style.display='block';

	return;
}