jquery.insert.coffee

do (jQuery) ->
  
  $ = jQuery

  insertAtCaret = (value) ->

    if document.selection # IE
      @focus()
      sel = document.selection.createRange()
      sel.text = value
      @focus()

    else if @selectionStart or @selectionStart is '0'
      startPos  = @selectionStart;
      endPos    = @selectionEnd;
      scrollTop = @scrollTop;

      @value = [
        @value.substring(0, startPos),
        value,
        @value.substring(endPos, @value.length)
      ].join ''

      @focus()
      @selectionStart = startPos + value.length
      @selectionEnd   = startPos + value.length
      @scrollTop      = scrollTop

    else
      throw new Error 'insertAtCaret not supported'

  $.fn.insertAtCaret = (value) ->
    $(this).each -> insertAtCaret.call(this, value)