function IsNumeric(strString)
//check for valid numeric strings	
{
	var strValidChars = "0123456789.-/ ";
	var strChar;
	var blnResult = true;
	if (strString.length == 0) return false;
	//test strString consists of valid characters listed above
	for (i = 0; i < strString.length && blnResult == true; i++)
	{
		strChar = strString.charAt(i);
		if (strValidChars.indexOf(strChar) == -1)
		{
			blnResult = false;
		}
	}
	return blnResult;
}

function ViewBook()
{
	
	if (document.getElementById("txtViewLstName").value == "")
	{
		alert("Please Enter Your Last Name!");
		document.getElementById("txtViewLstName").focus();
		return false;
	}
	var arrHr = document.getElementById("txtViewLstName").value;
	
	for(var j=0;j<arrHr.length;j++)
	{
		if((arrHr.charAt(j)>="a" && arrHr.charAt(j)<="z") || (arrHr.charAt(j)>="A" && arrHr.charAt(j)<="Z") || (arrHr.charAt(j)>="0" && arrHr.charAt(j)<="9") || (arrHr.charAt(j)== " "))
			;
		else
		{
			alert("Last Name accepts only Numbers and Alphabets");
			document.getElementById("txtViewLstName").focus(); 
			return false;
		}	
	}
	if (document.getElementById("txtViewResNo").value == "")
	{
		alert("Please Enter Your Reservation Number!");
		document.getElementById("txtViewResNo").focus();
		return false;
	}
	if (IsNumeric(document.getElementById("txtViewResNo").value) == false) 
	{
		alert("Please check - non numeric value in Reservation Number!");
		document.getElementById("txtViewResNo").focus();
		return false;
	}				
}


function AmendBook()
{
	if (document.getElementById("txtAmentLstName").value == "")
	{
		alert("Please Enter Your Last Name!");
		document.getElementById("txtAmentLstName").focus();
		return false;
	}
	var arrHr = document.getElementById("txtAmentLstName").value;
	for(var j=0;j<arrHr.length;j++)
	{
		if((arrHr.charAt(j)>="a" && arrHr.charAt(j)<="z") || (arrHr.charAt(j)>="A" && arrHr.charAt(j)<="Z") || (arrHr.charAt(j)>="0" && arrHr.charAt(j)<="9") || (arrHr.charAt(j)== " "))
			;
		else
		{
			alert("Last Name accepts only Numbers and Alphabets");
			document.getElementById("txtAmentLstName").focus(); 
			return false;
		}	
	}
	if (document.getElementById("txtAmentResNo").value == "")
	{
		alert("Please Enter Your Reservation Number!");
		document.getElementById("txtAmentResNo").focus();
		return false;
	}
	if (IsNumeric(document.getElementById("txtAmentResNo").value) == false) 
	{
		alert("Please check - non numeric value in Reservation Number!");
		document.getElementById("txtAmentResNo").focus();
		return false;
	}				
}


function CancelBook()
{
	if (document.getElementById("txtCancelLstName").value == "")
	{
		alert("Please Enter Your Last Name!");
		document.getElementById("txtCancelLstName").focus();
		return false;
	}
	var arrHr = document.getElementById("txtCancelLstName").value;
	for(var j=0;j<arrHr.length;j++)
	{
		if((arrHr.charAt(j)>="a" && arrHr.charAt(j)<="z") || (arrHr.charAt(j)>="A" && arrHr.charAt(j)<="Z") || (arrHr.charAt(j)>="0" && arrHr.charAt(j)<="9") || (arrHr.charAt(j)== " "))
			;
		else
		{
			alert("Last Name accepts only Numbers and Alphabets");
			document.getElementById("txtCancelLstName").focus(); 
			return false;
		}	
	}
	if (document.getElementById("txtCancelResNo").value == "")
	{
		alert("Please Enter Your Reservation Number!");
		document.getElementById("txtCancelResNo").focus();
		return false;
	}
	if (IsNumeric(document.getElementById("txtCancelResNo").value) == false) 
	{
		alert("Please check - non numeric value in Reservation Number!");
		document.getElementById("txtCancelResNo").focus();
		return false;
	}				
}