SetAttribute issue in Internet Explorer

<script Language="JavaScript">
var inputs = 0;
document.getElementById("txtHidInputs").value=inputs;
function addContact(){
	
    var table = document.getElementById('contacts');

    var tr    = document.createElement('TR');
    
    var td1   = document.createElement('TD');
    var td2   = document.createElement('TD');
    var td3   = document.createElement('TD');
    var td4   = document.createElement('TD');
    var td5   = document.createElement('TD');
    
    var inp1  = document.createElement('SELECT');
    var inp2  = document.createElement('SELECT');
    var inp3  = document.createElement('INPUT');
    var inp4  = document.createElement('SELECT');

	var opt1 = document.createElement('OPTION');
	var opt4 = document.createElement('OPTION');
	var opt5 = document.createElement('OPTION');
	var opt6 = document.createElement('OPTION');

    //if(inputs>0){
		var img = document.createElement('IMG');
        img.setAttribute('src', 'delete.gif');
        img.onclick = function(){
			removeContact(tr);
        }
        td1.appendChild(img);
    //}

    inp1.setAttribute("FieldList", "FieldList" +inputs);
    inp2.setAttribute("Conditions", "Conditions"+inputs);
    inp3.setAttribute("ConditionValue", "ConditionValue"+inputs);
    inp4.setAttribute("LogicalOperator", "LogicalOperator"+inputs);
    
    opt1.text="sdfsdfsdf";
    opt1.value="test";
    inp1.options.add(opt1);
    
    opt4.text="AND";
    opt4.value="AND";
    inp4.options.add(opt4);
    
    opt5.text="OR";
    opt5.value="OR";
    inp4.options.add(opt5);
    
       inp4.setAttribute('onChange', 'javascript:addContact()');
    //  inp4.addEventListener('onChange','addContact');
    
    table.appendChild(tr);
    tr.appendChild(td1);
    tr.appendChild(td2);
    tr.appendChild(td3);
    tr.appendChild(td4);
    tr.appendChild(td5);
    
    td2.appendChild(inp1);
    td3.appendChild(inp2);
    td4.appendChild(inp3);
    td5.appendChild(inp4);

    inputs++;
    document.getElementById("txtHidInputs").value=inputs;
}
function removeContact(tr)
{
	 inputs--;
	 document.getElementById("txtHidInputs").value=inputs;
     tr.parentNode.removeChild(tr);
  }

</Script>
<table>
   <tbody id="contacts">
      <tr>
         <td colspan="3"><a href="javascript:addContact();">Add a Contact</a></td>
      </tr>
      <tr>
         <td></td>
         <td>FieldList</td>
         <td>Conditions</td>
         <td>Condition Value</td>
         <td>Logical Operator</td>
      </tr>
      <input type="text" name="txtHidInputs" id="txtHidInputs" value="0">
   </tbody>
</table>

inp4.onchange = function() {
  addContact();
}