library/core/class.form.php
public function AddHidden($FieldName, $Value = NULL, $ForceValue = FALSE) {
      if ($this->IsPostBack() && $ForceValue === FALSE)
         $Value = $this->GetFormValue($FieldName, $Value);

      $this->HiddenInputs[$FieldName] = $Value;
   }
public function AddHidden($FieldName, $Value = NULL, $ForceValue = FALSE) {
      if ($this->IsPostBack() && $ForceValue === FALSE)
         $Value = $this->GetFormValue($FieldName, $Value);

      $this->HiddenInputs[$FieldName] = $Value;
   }
public function AddHidden ( $ FieldName , $ Value = NULL , $ ForceValue = FALSE ) { if ( $ this -> IsPostBack ( ) && $ ForceValue === FALSE ) $ Value = $ this -> GetFormValue ( $ FieldName , $ Value ) ; $ this -> HiddenInputs [ $ FieldName ] = $ Value ; }
Adds a hidden input value to the form.

If the $ForceValue parameter remains FALSE, it will grab the value into the hidden input from the form
on postback. Otherwise it will always force the assigned value to the
input regardless of postback.

@param string $FieldName The name of the field being added as a hidden input on the form.
@param string $Value The value being assigned in the hidden input. Unless $ForceValue is
changed to TRUE, this field will be retrieved from the form upon
postback.
@param bool $ForceValue
Adds a hidden input value to the form .