regplax - simple javascript text replacing utility, regular expressions based featuring GUI for return function

Input:

Search_Pattern:

RX_ON: Flags:

Replace_Pattern:

…is a function:(?) with arguments:

Controls:

Loop:

The Function (edit it if you want):

window.regplax = function ()
{ try
  { var form = document.forms[0]
  , input = form.Input
  , output = input
  , Flags = form.Flags.value
  , pattern
  = form.RX_ON.checked
    ? form.Search_Pattern.value
    : pattern.replace( /(\W)/g , '\\$1' )
    // ^ using RX for disabling RX. funny.
  , searchRg = new RegExp( pattern , Flags )
  , replaceSt
  = form.ptrn_is_fnc.checked
    // HAHAHAHA, deep dark practices follows:
    ? eval
      ( "new Function(\""
      + form.ptrn_is_fnc_params.value.split(/,\s*/).join("\",\"")
      + "\",\""
      + form.Replace_Pattern.value.replace(/(")/g,'\\$1').replace(/\n/g,' ')
      + "\")"
      )
    // p.s.: HAHAHAHA.
    : form.Replace_Pattern.value
  , buff = input.value.replace( searchRg , replaceSt )
  ; if ( form.loop.checked )
    { var lastVal
    ; while( buff.search(searchRg) > -1 )
      // searchRg.test(buff) behaves strange in IE6 and O9. gotta look at it
      { lastVal = buff
      ; buff = buff.replace( searchRg , replaceSt )
      ; if ( lastVal === buff ) throw new Error( 'Potentially (?) infinite loop terminated.' )
      }
    }
  ; output.value = buff
 }
 catch ( e )
 { alert( e + '\n -- regplax function' )
 }
}

Hints

Undo = ctrl+z in focused textarea (in most browsers; it may behave differently but generally it works. wee!)
For highliting matches use regexpal. Gotta grab that & exploit it here }:)
MDC:replace