// create object
function formValidator()
{
// set up array to hold error messages
this.errorList = new Array;
// set up object methods
this.isEmpty = isEmpty; 
this.isNumber = isNumber; 
this.isAlphabetic = isAlphabetic; 
this.isAlphaNumeric = isAlphaNumeric; 
this.isWithinRange = isWithinRange; 
this.isEmailAddress = isEmailAddress; 
this.isChecked = isChecked; 
this.raiseError = raiseError; 
this.numErrors = numErrors; 
this.displayErrors = displayErrors; 
}
// check to see if input is whitespace only or empty
function isEmpty(val)
{
if (val.match(/^s+$/) || val == "")
{
return true;
}
else
{
return false;
} 
}
// check to see if input is number
function isNumber(val)
{
if (isNaN(val))
{
return false;
}
else
{
return true;
} 
}
// check to see if input is alphabetic
function isAlphabetic(val)
{
if (val.match(/^[a-zA-Z]+$/))
{
return true;
}
else
{
return false;
} 
}
// check to see if input is alphanumeric
function isAlphaNumeric(val)
{
if (val.match(/^[a-zA-Z0-9]+$/))
{
return true;
}
else
{
return false;
} 
}
// check to see if value is within range
function isWithinRange(val, min, max)
{
if (val >= min && val <= max)
{
return true;
}
else
{
return false;
} 
}
// check to see if input is a valid email address
function isEmailAddress(val)
{
if (val.match(/^([a-zA-Z0-9])+([.a-zA-Z0-9_-])*@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-]+)+/))
{
return true;
}
else
{
return false;
} 
}
// check to see if form value is checked
function isChecked(obj)
{
if (obj.checked)
{
return true;
}
else
{
return false;
} 
}
// display all errors
// iterate through error array and print each item
function displayErrors()
{
for (x=0; x<this.errorList.length; x++)
{
alert("Error: " + this.errorList[x]);
}
}
// add an error to error list
function raiseError(msg)
{
this.errorList[this.errorList.length] = msg;
}
// return number of errors in error array
function numErrors()
{
return this.errorList.length;
}
// end object
function check_form(form_name){
    // instantiate object
    fv = new formValidator();
    for(i=0;i<form_name.elements.length;i++){
        if (fv.isEmpty(form_name.elements[i].value))
        {
            if(form_name.elements[i].className=="mandatory"){
                fv.raiseError(EmptyError + "!");
                form_name.elements[i].focus(); 
                fv.displayErrors();
                return false;
            }        
        }
        str=form_name.elements[i].name.toLowerCase();
        if((str.search("email")!=-1)){
            if(!fv.isEmailAddress(form_name.elements[i].value)){
                fv.raiseError(EmailError + "!");
                form_name.elements[i].focus(); 
                fv.displayErrors();
                return false;    
            }
        } 
    }
return true;
}