User:Writ Keeper/Scripts/summaryEnterStopper.js

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//design for this largely cribbed from http://webcheatsheet.com/javascript/disable_enter_key.php

function disableEnterKey(e)
{
  var evt = e;
  if(evt == null)
  {
    evt = event;
  }
  if(evt != null && evt.keyCode == 13)
  {
    return false;
  }
}

(function(){
  var editSummary = $("#wpSummary");
  if(editSummary.length > 0)
  {
    editSummary = editSummary[0];
    editSummary.onkeypress = disableEnterKey;
  }
})();