JQUERY error : null or not an object. Any Jquery Ninjas that can help?

Question

Any JQUERY NINJA's out there?

Getting an error in IE ?

'tip' is null or not an object

Here is the small script:

  $(document).ready(function() {
       //Tooltips
        var tip;
        $(".tip_trigger").hover(function(){

            //Caching the tooltip and removing it from container; then appending it to the body
            tip = $(this).find('.tip').remove();
            $('body').append(tip);

            tip.show(); //Show tooltip


        }, function() {

            tip.hide().remove(); //Hide and remove tooltip appended to the body
            $(this).append(tip); //Return the tooltip to its original position

        }).mousemove(function(e) {
        //console.log(e.pageX)
              var mousex = e.pageX + 20; //Get X coodrinates
              var mousey = e.pageY + 20; //Get Y coordinates
              var tipWidth = tip.width(); //Find width of tooltip
              var tipHeight = tip.height(); //Find height of tooltip

             //Distance of element from the right edge of viewport
              var tipVisX = $(window).width() - (mousex + tipWidth);
              var tipVisY = $(window).height() - (mousey + tipHeight);

            if ( tipVisX < 20 ) { //If tooltip exceeds the X coordinate of viewport
                mousex = e.pageX - tipWidth - 20;
                $(this).find('.tip').css({  top: mousey, left: mousex });
            } if ( tipVisY < 20 ) { //If tooltip exceeds the Y coordinate of viewport
                mousey = e.pageY - tipHeight - 20;
                tip.css({  top: mousey, left: mousex });
            } else {
                tip.css({  top: mousey, left: mousex });
            }
        });

    });

Updated Code:(Can't seem to integrate your updated code into this)

$(document).ready(function() {
   //Tooltips
    var tip = null;

    $(".tip_trigger").hover(function(){

        //Caching the tooltip and removing it from container; then appending it to the body
        tip = $(this).find('.tip').remove();
        $('body').append(tip);

        tip.show(); //Show tooltip


    }, function() {

        tip.hide().remove(); //Hide and remove tooltip appended to the body
        $(this).append(tip); //Return the tooltip to its original position

    }).mousemove(function(e) {
    //console.log(e.pageX)
          if ( tip == null ) return;


          var mousex = e.pageX + 20; //Get X coodrinates
          var mousey = e.pageY + 20; //Get Y coordinates
          var tipWidth = tip.width(); //Find width of tooltip
          var tipHeight = tip.height(); //Find height of tooltip

         //Distance of element from the right edge of viewport
          var tipVisX = $(window).width() - (mousex + tipWidth);
          var tipVisY = $(window).height() - (mousey + tipHeight);

        if ( tipVisX < 20 ) { //If tooltip exceeds the X coordinate of viewport
            mousex = e.pageX - tipWidth - 20;
            $(this).find('.tip').css({  top: mousey, left: mousex });
        } if ( tipVisY < 20 ) { //If tooltip exceeds the Y coordinate of viewport
            mousey = e.pageY - tipHeight - 20;
            tip.css({  top: mousey, left: mousex });
        } else {
            tip.css({  top: mousey, left: mousex });
        }
    });

});

Answer 1

$(function() {

    $('.tip_trigger').each(function() {        
        var tip = $(this).find('.tip');

        $(this).hover(
            function() { tip.appendTo('body'); },
            function() { tip.appendTo(this); }
        ).mousemove(function(e) {
            var x = e.pageX + 20,
                y = e.pageY + 20,
                w = tip.width(),
                h = tip.height(),
                dx = $(window).width() - (x + w),
                dy = $(window).height() - (y + h);

            if ( dx < 20 ) x = e.pageX - w - 20;
            if ( dy < 20 ) y = e.pageY - h - 20;

            tip.css({ left: x, top: y });
        });         
    });

});

Live demo: http://jsfiddle.net/vNBNz/4/

As you can see, the above code works. In the live demo, notice this CSS rule:

.tip_trigger .tip { display:none; }

The above rule will hide all .tip elements, but only if they are inside a .tip_trigger element. This means that as soon as you append a .tip element to the BODY, it will be displayed because the "hide-rule" only applies to .tip elements inside .tip_trigger.

Answer 2

This is because in IE move can happen before hover. Try out this example. I did not reproduce this functionality in Chrome. And my IE test was IE9 beta.

So my guess is that it is failing on this line:

var tipWidth = tip.width();

Of the mousemove callback because var tip; is still undefined.