// Cross-browser event handling

// by Scott Andrew LePera

// http://www.scottandrew.com/weblog/articles/cbs-events



// Modified 2004-08-10 by Andrew Grgeory to work around Konqueror bug

// Modified 2004-06-04 by Andrew Gregory to support legacy (NS3,4) browsers

// http://www.scss.com.au/family/andrew/



// eg. addEvent(imgObj, 'mousedown', processEvent, false);

function addEvent(obj, evType, fn, useCapture) {

  // work around Konqueror bug #57913 which prevents

  // window.addEventListener('load',...) from working

  var ua = navigator.userAgent;

  var konq = ua.indexOf('KHTML') != -1 && ua.indexOf('Safari') == -1 && obj == window && evType == 'load';

  // don't use addEventListener for Konq, have Konq fall back to the old

  // obj.onload method

  if (obj.addEventListener && !konq) {

    obj.addEventListener(evType, fn, useCapture);

    return true;

  } else if (obj.attachEvent) {

    return obj.attachEvent('on' + evType, fn);

  } else {

    if (!obj.cb_events) {

      obj.cb_events = new Object();

      obj.cb_ftemp = null;

    }

    var events = obj.cb_events[evType];

    if (!events) {

      events = new Array();

      obj.cb_events[evType] = events;

    }

    var i = 0;

    while ((i < events.length) && (events[i] != fn)) {

      i++;

    }

    if (i == events.length) {

      events[i] = fn;

      obj['on' + evType] = new Function("var ret=false,e=this.cb_events['"+evType+"'];if(e){for(var i=0;i<e.length;i++){this.cb_ftemp=e[i];ret=this.cb_ftemp()||ret;}return ret;}");

    }

    return true;

  }

}



// eg. removeEvent(imgObj, 'mousedown', processEvent, false);

function removeEvent(obj, evType, fn, useCapture) {

  // work around Konqueror bug #57913 which prevents

  // window.addEventListener('load',...) from working

  var ua = navigator.userAgent;

  var konq = ua.indexOf('KHTML') != -1 && ua.indexOf('Safari') == -1 && obj == window && evType == 'load';

  // don't use addEventListener for Konq, have Konq fall back to the old

  // obj.onload method

  if (obj.removeEventListener && !konq) {

    obj.removeEventListener(evType, fn, useCapture);

    return true;

  } else if (obj.detachEvent) {

    return obj.detachEvent('on' + evType, fn);

  } else {

    var ret = false;

    if (obj.cb_events) {

      var events = obj.cb_events[evType];

      if (events) {

        // remove any matching functions from the events array, shuffling items

        // down to fill in the space before truncating the array

        var dest = 0;

        for (var src = 0; src < events.length; src++) {

          if (dest != src) {

            events[dest] = events[src];

          }

          if (events[dest] == fn) {

            ret = true;

          } else {

            dest++;

          }

        }

        events.length = dest;

      }

    }

    return ret;

  }

}