function LTrim(str) { 
 for (var k=0; k<str.length && str.charAt(k)<=" " ; k++) ;
 return str.substring(k,str.length);
}

function RTrim(str) {
 for (var j=str.length-1; j>=0 && str.charAt(j)<=" " ; j--) ;
 return str.substring(0,j+1);
}

function Trim(str) {
 return LTrim(RTrim(str));
}


function nameSelect()
{
 if (isBlank("" + document.supplier.co_name.value)) {
    document.supplier.co_name.value="Company Name"
	document.supplier.co_name.focus()
	document.supplier.co_name.select()
 }
}
	
function isBlank(s) {
	var len=s.length
	var i
	for (i=0;i<len;++i) {
		if (s.charAt(i) != " ") return false
	}
	return true
}

function validate(fieldName,fieldValue) {
	if (isBlank(fieldValue)) {
		alert(fieldName + " cannot be left blank.")
		return false
	}
	return true
}

function validateEmail(fieldName, m) {
	var s = Trim(m)
	var len = s.length
	var i, count
	count = 0
	for (i=0;i<len;++i) {
		if (s.charAt(i) == '@')  ++count
		if (s.charAt(i) == " ")  {
			alert(fieldName + " is not a valid email address.")
			return false
		}
	}
	if (count != 1) {
		alert(fieldName + " is not a valid email address.") 
		return false
	}
	return true
}



function validateNum(fieldName,m) {
	var s = Trim(m)
	var len = s.length
	var i
	for (i=0;i<len;++i) {
		 switch (s.charAt(i)) {
			  case "0":
			     break
			  case "1":
			     break
		      case "2":
			     break
			  case "3":
			      break
			  case "4":
			      break
			  case "5":
			      break
			  case "6":
			      break
			  case "7":
			      break
			  case "8":
			      break
			  case "9":
			      break
			  default:
			      alert(fieldName + " must only contain numbers 0-9 and have no spaces between numbers.")
			      return false
		    }
	 }
	 return true
 }



function validateCompanyName() {
   validate("The company name field",document.supplier.co_name.value)
}



  
function validateForm() {
	if (!validate("The customer code field", document.payment.item_number.value)) {
	   document.payment.item_number.focus()
	   return false
	  
	}
	
	
}


//make a pop-up window function