//keep around the old call function
xajax.realCall = xajax.call;
//override the call function to bend to our wicked ways
xajax.call = function(sFunction, aArgs, sRequestType)
{
    //show the spinner
    this.$('indicator').style.display = '';
    this.$('button_submit').style.display = 'none';

    //call the old call function
    this.realCall(sFunction, aArgs, sRequestType);
}

//save the old processResponse function for later
xajax.realProcessResponse = xajax.processResponse;
//override the processResponse function
xajax.processResponse = function(xml)
{
    //hide the spinner
    this.$('indicator').style.display = 'none';
    this.$('button_submit').style.display = '';
    //call the real processResponse function
    this.realProcessResponse(xml);
}