function Validator(frmname)
{
	this.formobj=document.forms[frmname];
	if(!this.formobj)
	{
		alert("BUG: couldnot get Form object "+frmname);
		return;
	}
	if(this.formobj.onsubmit)
	{
		this.formobj.old_onsubmit = this.formobj.onsubmit;
		this.formobj.onsubmit=null;
	}
	else
	{
		this.formobj.old_onsubmit = null;
	}
	this.formobj.onsubmit=form_submit_handler;
	this.addValidation = add_validation;
	this.setAddnlValidationFunction=set_addnl_vfunction;
	this.clearAllValidations = clear_all_validations;
}

function set_addnl_vfunction(functionname)
{
	this.formobj.addnlvalidation = functionname;
}

function clear_all_validations()
{
	for(var itr=0;itr < this.formobj.elements.length;itr++)
	{
		this.formobj.elements[itr].validationset = null;
	}
}

function form_submit_handler()
{
	for(var itr=0;itr < this.elements.length;itr++)
	{
		if(this.elements[itr].validationset && !this.elements[itr].validationset.validate())
		{
			return false;
		}
	}
	if(this.addnlvalidation)
	{
		str =" var ret = "+this.addnlvalidation+"()";
		eval(str);
		if(!ret) return ret;
	}
	return true;
}

function add_validation(itemname,descriptor,errstr)
{
	if(!this.formobj)
	{
		alert("BUG: the form object is not set properly");
		return;
	}//if
	var itemobj = this.formobj[itemname];
	if(itemobj.length && isNaN(itemobj.selectedIndex) )
	//for radio button; don't do for 'select' item
	{
		itemobj = itemobj[0];
	}
	if(!itemobj)
	{
		alert("BUG: Couldnot get the input object named: "+itemname);
		return;
	}
	if(!itemobj.validationset)
	{
		itemobj.validationset = new ValidationSet(itemobj);
	}
	itemobj.validationset.add(descriptor,errstr);
}

function ValidationDesc(inputitem,desc,error)
{
	this.desc=desc;
	this.error=error;
	this.itemobj = inputitem;
	this.validate=vdesc_validate;
}

function vdesc_validate()
{
	if(!validateInput(this.desc,this.itemobj,this.error))
	{
		this.itemobj.focus();
		return false;
	}
	return true;
}

function ValidationSet(inputitem)
{
	this.vSet=new Array();
	this.add= add_validationdesc;
	this.validate= vset_validate;
	this.itemobj = inputitem;
}

function add_validationdesc(desc,error)
{
	this.vSet[this.vSet.length]= new ValidationDesc(this.itemobj,desc,error);
}

function vset_validate()
{
	for(var itr=0;itr<this.vSet.length;itr++)
	{
		if(!this.vSet[itr].validate())
		{
			return false;
		}
	}
	return true;
}

/*  checks the validity of an email address entered
*   returns true or false
*/
function validateEmail(email)
{
	var splitted = email.match("^(.+)@(.+)$");
	if(splitted == null) return false;
	if(splitted[1] != null )
	{
		var regexp_user=/^\"?[\w-_\.]*\"?$/;
		if(splitted[1].match(regexp_user) == null) return false;
	}
	if(splitted[2] != null)
	{
		var regexp_domain=/^[\w-\.]*\.[A-Za-z]{2,4}$/;
		if(splitted[2].match(regexp_domain) == null)
		{
			var regexp_ip =/^\[\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\]$/;
			if(splitted[2].match(regexp_ip) == null)
				return false;
		}// if
		return true;
	}
	return false;
}

function TestComparison(objValue,strCompareElement,strvalidator,strError)
{
	var bRet=true;
	var objCompare=null;
	if(!objValue.form)
	{
		alert("BUG: No Form object!");
		return false
	}
	objCompare = objValue.form.elements[strCompareElement];
	if(!objCompare)
	{
		alert("BUG: Element with name"+strCompareElement+" not found !");
		return false;
	}
	if(strvalidator != "eqelmnt" && strvalidator != "neelmnt")
	{
		if(isNaN(objValue.value))
		{
			alert(objValue.name+": Should be a number ");
			return false;
		}//if
		if(isNaN(objCompare.value))
		{
			alert(objCompare.name+": Should be a number ");
			return false;
		}//if
	}//if
	var cmpstr="";
	switch(strvalidator)
	{
		case "eqelmnt":
		{
			if(objValue.value != objCompare.value)
			{
				cmpstr = " should be equal to ";
				bRet = false;
			}//if
			break;
		}//case
		case "ltelmnt":
		{
			if(eval(objValue.value) >= eval(objCompare.value))
			{
				cmpstr =  " should be less than ";
				bRet = false;
			}
			break;
		}//case
		case "leelmnt":
		{
			if(eval(objValue.value) >  eval(objCompare.value))
			{
				cmpstr =  " should be less than or equal to";
				bRet = false;
			}
			break;
		}//case
		case "gtelmnt":
		{
			if(eval(objValue.value) <=  eval(objCompare.value))
			{
				cmpstr =  " should be greater than";
				bRet = false;
			}
			break;
		}//case
		case "geelmnt":
		{
			if(eval(objValue.value) < eval(objCompare.value))
			{
				cmpstr =  " should be greater than or equal to";
				bRet = false;
			}
			break;
		}//case
		case "neelmnt":
		{
			if(objValue.value.length > 0 &&	objCompare.value.length > 0 &&	objValue.value == objCompare.value)
			{
				cmpstr = " should be different from ";
				bRet = false;
			}//if
			break;
		}
	}//switch
	if(bRet==false)
	{
		if(!strError || strError.length==0)
		{
			strError = objValue.name + cmpstr + objCompare.value;
		}//if
		alert(strError);
	}//if
	return bRet;
}

function TestSelMin(objValue,strMinSel,strError)
{
	var bret = true;
	var objcheck = objValue.form.elements[objValue.name];
	var chkcount =0;
	if(objcheck.length)
	{
		for(var c=0;c < objcheck.length;c++)
		{
			if(objcheck[c].checked == "1")
			{
				chkcount++;
			}//if
		}//for
	}
	else
	{
		chkcount = (objcheck.checked == "1")?1:0;
	}
	var minsel = eval(strMinSel);
	if(chkcount < minsel)
	{
		if(!strError || strError.length ==0)
		{
			strError = "Please Select atleast"+minsel+" check boxes for"+objValue.name;
		}//if
		alert(strError);
		bret = false;
	}
	return bret;
}

function TestDontSelectChk(objValue,chkValue,strError)
{
	var pass=true;
	var objcheck = objValue.form.elements[objValue.name];
	if(objcheck.length)
	{
		var idxchk=-1;
		for(var c=0;c < objcheck.length;c++)
		{
			if(objcheck[c].value == chkValue)
			{
				idxchk=c;
				break;
			}//if
		}//for
		if(idxchk>= 0)
		{
			if(objcheck[idxchk].checked=="1")
			{
				pass=false;
			}
		}//if
	}
	else
	{
		if(objValue.checked == "1")
		{
			pass=false;
		}//if
	}//else
	if(pass==false)
	{
		if(!strError || strError.length ==0)
		{
			strError = "Can't Proceed as you selected "+objValue.name;
		}//if
		alert(strError);
	}
	return pass;
}

function TestRequiredInput(objValue,strError)
{
	var ret = true;
	if(eval(objValue.value.length) == 0)
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name + " : Required Field";
		}//if
		alert(strError);
		ret=false;
	}//if
	return ret;
}

function TestMaxLen(objValue,strMaxLen,strError)
{
	var ret = true;
	if(eval(objValue.value.length) > eval(strMaxLen))
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name + " : "+ strMaxLen +" characters maximum ";
		}//if
		alert(strError + "\n[Current length = " + objValue.value.length + " ]");
		ret = false;
	}//if
	return ret;
}

function TestMinLen(objValue,strMinLen,strError)
{
	var ret = true;
	if(eval(objValue.value.length) <  eval(strMinLen))
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name + " : " + strMinLen + " characters minimum  ";
		}//if
		alert(strError + "\n[Current length = " + objValue.value.length + " ]");
		ret = false;
	}//if
	return ret;
}

function TestInputType(objValue,strRegExp,strError,strDefaultError)
{
	var ret = true;
	var charpos = objValue.value.search(strRegExp);
	if(objValue.value.length > 0 &&  charpos >= 0)
	{
		if(!strError || strError.length ==0)
		{
			strError = strDefaultError;
		}//if
		alert(strError + "\n [Error character position " + eval(charpos+1)+"]");
		ret = false;
	}//if
	return ret;
}

function TestEmail(objValue,strError)
{
	var ret = true;
	if(objValue.value.length > 0 && !validateEmail(objValue.value)	 )
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name+": Enter a valid Email address ";
		}//if
		alert(strError);
		ret = false;
	}//if
	return ret;
}

function TestLessThan(objValue,strLessThan,strError)
{
	var ret = true;
	if(isNaN(objValue.value))
	{
		alert(objValue.name+": Should be a number ");
		ret = false;
	}//if
	else
	if(eval(objValue.value) >=  eval(strLessThan))
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name + " : value should be less than "+ strLessThan;
		}//if
		alert(strError);
		ret = false;
	}//if
	return ret;
}

function TestGreaterThan(objValue,strGreaterThan,strError)
{
	var ret = true;
	if(isNaN(objValue.value))
	{
		alert(objValue.name+": Should be a number ");
		ret = false;
	}//if
	else
	if(eval(objValue.value) <=  eval(strGreaterThan))
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name + " : value should be greater than "+ strGreaterThan;
		}//if
		alert(strError);
		ret = false;
	}//if
	return ret;
}

function TestRegExp(objValue,strRegExp,strError)
{
	var ret = true;
	if( objValue.value.length > 0 && !objValue.value.match(strRegExp) )
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name+": Invalid characters found ";
		}//if
		alert(strError);
		ret = false;
	}//if
	return ret;
}

function TestDontSelect(objValue,index,strError)
{
	var ret = true;
	if(objValue.selectedIndex == null)
	{
		alert("BUG: dontselect command for non-select Item");
		ret = false;
	}
	else if(objValue.selectedIndex == eval(index))
	{
		if(!strError || strError.length ==0)
		{
			strError = objValue.name+": Please Select one option ";
		}//if
		alert(strError);
		ret =  false;
	}
	return ret;
}

function TestSelectOneRadio(objValue,strError)
{
	var objradio = objValue.form.elements[objValue.name];
	var one_selected=false;
	for(var r=0;r < objradio.length;r++)
	{
		if(objradio[r].checked == "1")
		{
			one_selected=true;
			break;
		}
	}
	if(false == one_selected)
	{
		if(!strError || strError.length ==0)
		{
			strError = "Please select one option from "+objValue.name;
		}
		alert(strError);
	}
	return one_selected;
}

//*  Checks each field in a form
function validateInput(strValidateStr,objValue,strError)
{
	var ret = true;
	var epos = strValidateStr.search("=");
	var  command  = "";
	var  cmdvalue = "";
	if(epos >= 0)
	{
		command  = strValidateStr.substring(0,epos);
		cmdvalue = strValidateStr.substr(epos+1);
	}
	else
	{
		command = strValidateStr;
	}
	switch(command)
	{
		case "req":
		case "required":
		{
			ret = TestRequiredInput(objValue,strError)
			break;
		}
		case "maxlength":
		case "maxlen":
		{
			ret = TestMaxLen(objValue,cmdvalue,strError)
			break;
		}
		case "minlength":
		case "minlen":
		{
			ret = TestMinLen(objValue,cmdvalue,strError)
			break;
		}
		case "alnum":
		case "alphanumeric":
		{
			ret = TestInputType(objValue,"[^A-Za-z0-9]",strError, objValue.name+": Only alpha-numeric characters allowed ");
			break;
		}
		case "alnum_s":
		case "alphanumeric_space":
		{
			ret = TestInputType(objValue,"[^A-Za-z0-9\\s]",strError, objValue.name+": Only alpha-numeric characters and space allowed ");
			break;
		}
		case "num":
		case "numeric":
		{
			ret = TestInputType(objValue,"[^0-9]",strError, objValue.name+": Only digits allowed ");
			break;
		}
		case "alphabetic":
		case "alpha":
		{
			ret = TestInputType(objValue,"[^A-Za-z]",strError, objValue.name+": Only alphabetic characters allowed ");
			break;
		}
		case "alphabetic_space":
		case "alpha_s":
		{
			ret = TestInputType(objValue,"[^A-Za-z\\s]",strError, objValue.name+": Only alphabetic characters and space allowed ");
			break;
		}
		case "email":
		{
			ret = TestEmail(objValue,strError);
			break;
		}
		case "lt":
		case "lessthan":
		{
			ret = TestLessThan(objValue,cmdvalue,strError);
			break;
		}
		case "gt":
		case "greaterthan":
		{
			ret = TestGreaterThan(objValue,cmdvalue,strError);
			break;
		}
		case "regexp":
		{
			ret = TestRegExp(objValue,cmdvalue,strError);
			break;
		}
		case "dontselect":
		{
			ret = TestDontSelect(objValue,cmdvalue,strError)
			break;
		}
		case "dontselectchk":
		{
			ret = TestDontSelectChk(objValue,cmdvalue,strError)
			break;
		}
		case "selmin":
		{
			ret = TestSelMin(objValue,cmdvalue,strError);
			break;
		}
		case "selone":
		{
			ret = TestSelectOneRadio(objValue,strError);
			break;
		}
		//Comparisons
		case "eqelmnt":
		case "ltelmnt":
		case "leelmnt":
		case "gtelmnt":
		case "geelmnt":
		case "neelmnt":
		{
			return TestComparison(objValue,cmdvalue,command,strError);
			break;
		}
	}//switch
	return ret;
}