function roll(img_name, img_src){
  document[img_name].src = img_src;
  }

function verifyForm(frm){
    if(
        isNotEmpty(frm.Name, 'T') &&
        isNotEmpty(frm.Email, 'T') &&
	isEmail(frm.Email) &&
        isNotEmpty(frm.Phone, 'T')  
    ){
      return true;
    }else return false;
}

function isCorrectLength(inputVal, correctlength){
	if(inputVal.value.length != correctlength){
		alert("Value is invalid length. It should be "+correctlength);
		inputVal.focus();
		inputVal.select();
		return false;
	}
	return true;
}

function isEmail(email){
	val = email.value;
	invalidChars = " /:,;";
	msg = "Invalid email address! Must be in format user@domain.ext";
	for(i=0; i < invalidChars.length; i++){
		badChar = invalidChars.charAt(i);
		if( val.indexOf(badChar, 0) > -1){
			alert(msg);
			email.focus();
			email.select();
			return false;
		}
	}

	atPos = val.indexOf("@", 1);
	if( atPos == -1){
		alert(msg);
		email.focus();
		email.select();
		return false;
	}

	if(val.indexOf("@", atPos+1)>-1){
		alert(msg);
		email.focus();
		email.select();
		return false;
	}

	periodPos = val.indexOf(".", atPos);
	if(periodPos == -1){
		alert(msg);
		email.focus();
		email.select();
		return false;
	}

	if(periodPos+3 > val.length){
		alert(msg);
		email.focus();
		email.select();
		return false;
	}
	return true;
}

function isNotEmpty(inputVal, type){
	if(inputVal.value == ""){
		alert("Required field; cannot be blank");
		inputVal.focus();
		if(type == "T"){
			inputVal.select();
		}
		return false;
	}
	return true;
}


function isNum(inputNum){
	val = inputNum.value;
	for(i=0; i < val.length; i++){
		if( (val.charAt(i) < "0" || val.charAt(i) > "9") && val.charAt(i) != "." ){
			alert("Input must be numeric");
			inputNum.focus();
			inputNum.select();
			return false;
		}
	}
	return true;
}


function stripLeadingDigit(inputNum){
  if( inputNum.value.charAt(0) =="1" )
  inputNum.value = inputNum.value.substring(1);
}

function stripPhoneDelimiters(inputNum){
    unformattednum="";
    for(i=0; i<inputNum.value.length;i++)
    {
        if(inputNum.value.charAt(i) >= "0" && inputNum.value.charAt(i) <= "9" )
        unformattednum+=inputNum.value.charAt(i);
    }
    inputNum.value=unformattednum;
}


function checkCheckbox(ckbx)
{

	if(!ckbx.checked){
		alert('You must agree to the terms of the rental agreement.');
		return false;
	}
	
	return true;
}