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")
   {
      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
   }//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[Longitud actual = " + 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[Longitud actual = " + 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 del caracter en la posición " + eval(charpos+1)+"]");
      ret = false; 
    }//if 
 return ret;
}

function TestEmail(objValue,strError)
{
var ret = true;
     if(!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.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":
                {
                    return TestComparison(objValue,cmdvalue,command,strError);
                break;
                }
    }//switch 
    return ret; 
}