全てのsubmitボタンダブルクリック防止[JavaScript][Prototype]

Event.observe(window, 'load', doubleClickLoadHandler, false);
function doubleClickLoadHandler(){
    inputTags  = document.getElementsByTagName("input");

    for(var i = 0 ; i < inputTags.length ; i++){
        if(inputTags[i].type == "submit"){
          Event.observe(inputTags[i],'click',doubleClickInputHandler);
        }
    }

    formTags  = document.getElementsByTagName("form");
    for(var i = 0 ; i < formTags.length ; i++){
      Event.observe(formTags[i],'submit',doubleClickFormHandler);
    }
}

function doubleClickInputHandler(e){
  var occurTag = Event.element(e);
  var formTag  = occurTag.form;
  var q = document.createElement('input');
  q.type = 'hidden';
  q.name = occurTag.name;
  q.value = occurTag.value;
  formTag.appendChild(q);
}

function doubleClickFormHandler(e){
  var formTag = Event.element(e);
  var submitTags = Form.getInputs(formTag,"submit");
  for( var i = 0 ; i < submitTags.length ; i ++){
    submitTags[i].disable();
  }
}