function preventSelection(element){
  var preventSelection = false;
    function addHandler(element, event, handler){
        if (element.attachEvent) 
              element.attachEvent('on' + event, handler);
                  else 
                        if (element.addEventListener) 
                                element.addEventListener(event, handler, false);
                                  }
                                    function removeSelection(){
                                        if (window.getSelection) { window.getSelection().removeAllRanges(); }
                                            else if (document.selection && document.selection.clear)
                                                  document.selection.clear();
                                                    }
                                                      function killCtrlA(event){
                                                          var event = event || window.event;
                                                              var sender = event.target || event.srcElement;
                                                              
                                                                  if (sender.tagName.match(/INPUT|TEXTAREA/i))
                                                                        return;
                                                                        
                                                                            var key = event.keyCode || event.which;
                                                                                if (event.ctrlKey && key == 'A'.charCodeAt(0)){
                                                                                      removeSelection();
                                                                                      
                                                                                            if (event.preventDefault) 
                                                                                                    event.preventDefault();
                                                                                                          else
                                                                                                                  event.returnValue = false;
                                                                                                                      }
                                                                                                                        }
                                                                                                                          addHandler(element, 'mousemove', function(){
                                                                                                                              if(preventSelection)
                                                                                                                                    removeSelection();
                                                                                                                                      });
                                                                                                                                        addHandler(element, 'mousedown', function(event){
                                                                                                                                            var event = event || window.event;
                                                                                                                                                var sender = event.target || event.srcElement;
                                                                                                                                                    preventSelection = !sender.tagName.match(/INPUT|TEXTAREA/i);
                                                                                                                                                      });
                                                                                                                                                        addHandler(element, 'mouseup', function(){
                                                                                                                                                            if (preventSelection)
                                                                                                                                                                  removeSelection();
                                                                                                                                                                      preventSelection = false;
                                                                                                                                                                        });
                                                                                                                                                                          addHandler(element, 'keydown', killCtrlA);
                                                                                                                                                                            addHandler(element, 'keyup', killCtrlA);
                                                                                                                                                                            }
                                                                                                                                                                            
                                                                                                                                                                            preventSelection(document);