function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}

function addOnClickEvent(id, func) {

  if(document.getElementById(id)) {
	var oldevent = document.getElementById(id).onclick;
    if (typeof document.getElementById(id).onclick != 'function') {
      document.getElementById(id).onclick = eval(func);
    } else {
      document.getElementById(id).onclick = function() {
      oldevent();
      func();
      }
    }
  }

}


function addOnSubmitEvent(id, func) {

  if(document.getElementById(id)) {
	var oldevent = document.getElementById(id).onsubmit;
    if (typeof document.getElementById(id).onsubmit != 'function') {
      document.getElementById(id).onsubmit = eval(func);
    } else {
      document.getElementById(id).onsubmit = function() {
      oldevent();
      func();
      }
    }

  }
}

function addOnChangeEvent(id, func) {

  if(document.getElementById(id)) {
	var oldevent = document.getElementById(id).onchange;
    if (typeof document.getElementById(id).onchange != 'function') {
      document.getElementById(id).onchange = eval(func);
    } else {
      document.getElementById(id).onchange = function() {
      oldevent();
      func();
      }
    }

  }
}

function addOnKeyDownEvent(id, func) {

  if(document.getElementById(id)) {
	var oldevent = document.getElementById(id).onkeydown;
    if (typeof document.getElementById(id).onkeydown != 'function') {
      document.getElementById(id).onkeydown = eval(func);
    } else {
      document.getElementById(id).onkeydown = function() {
      oldevent();
      func();
      }
    }

  }
}


function addOnFocusEvent(id, func) {

  if(document.getElementById(id)) {
	var oldevent = document.getElementById(id).onclick;
    if (typeof document.getElementById(id).onclick != 'function') {
      document.getElementById(id).onclick = eval(func);
    } else {
      document.getElementById(id).onclick = function() {
      oldevent();
      func();
      }
    }
  }

}