Reset sharepoint lookup with None option using jquery

Question

How to reset the lookup value to None in Editform.aspx page using Jquery.

I want to empty the lookup dropdown if text box does not have any value . Here is the code which i have tried.I was able to set the value but it is adding ('None') in the look up drop down. When i click on save it is showing the selected value .

Note: By lookup has more than 20+ items.

$("input[title='"+NumStoreColName+"']").change(function()
    {
         var NoStoreVals =$("input[title='"+NumStoreColName+"']").val();
        if(NoStoreVals == "")
         {

             ResetDropDownList(hidelookup); 
         }
         else
         {

         }      
    });


function ResetDropDownList(lookupcolumnName) 
{
    lookupField = getField('select',lookupcolumnName); 
     lookupSelectedItem = lookupField.options[lookupField.selectedIndex]; 
     var test= lookupSelectedItem.value + "-" + lookupSelectedItem.text; 
     lookupSelectedItem.text='(None)';
}

function getField(fieldType,fieldTitle) {  
      var docTags = document.getElementsByTagName(fieldType);  
      for (var i=0; i < docTags.length; i++) {  
          if (docTags[i].title == fieldTitle) {  
              return docTags[i];  
          }  
      }  
      return false;  
} 

Answer 1

I was able to get this working if my lookup has less tahn 20 items. However it is not working if i has more than 20 + items in Ie10.

function ResetDropDownList(lookupcolumnName,NumStoreColName) 
{

     if(getField('select',lookupcolumnName))
     {
         getField('input',NumStoreColName).value='';
         $("select[title='"+ lookupcolumnName +"'] option:eq(0)").attr('selected','(None)');

     }
  else  
    { 
    $("input[title='"+ lookupcolumnName +"'] option:eq(0)").attr('selected','(None)');
     getField('input',NumStoreColName).value='';
    }


}