[N.B. I posted this answer on the github page for the project on a similar question someone had raised. So check there in case this answer was corrected! - https://github.com/ducksboard/gridster.js/issues/74]
I spent the past few days with a similar issue - although I only needed IE8 support (though it seems to work in IE7). The issue was the code is updating the page correctly but IE would not pick-up/evaluate the data-row & data-col changes while the mouse was moving. I tried several things from the solution above, through to using modernizr & similar libraries and finally trying to bind to the IE only 'propertychange' event with no success.
It seems to be an IE8 limitation that it won't re-evaluate an element that is using CSS Attributes while the mouse is down/moving. However, it does detect class and in-line changes (which is why you can drag the box around).
Therefore the only solution I could find with the time available was to add/remove a fake class in the code whenever the widgets should be updated using jQuery .toggle(). So I added it in the code when the preview and widgets were passed new data-col & data-row attributes. This forces IE8 to pick up the change and voila the preview works.
Now I am sure there is a (much) better solution besides not using IE8 and it doesn't guarantee IE8 compatibility but if you're stuck then you may find this helpful!
p.s. I only had to worry about IE8+, IE7 seemed to be okay when using modernizr and similar plugins. However haven't tried in IE6 but I doubt it would work.
[EDIT]
Following the comment below I've now uploaded to an example - although I couldn't get IE8 to play nice with JSFiddle. So the example of it working in IE8 is here instead :
https://s3-eu-west-1.amazonaws.com/707074webfiles/gridster/ie8test.html
I have included IE9.js which (mostly) adds the transparency effect for the preview in this instance.
The modified copy of the gridster.js file is here:
https://github.com/Grozzer/gridster.js/blob/master/dist/jquery.gridster.js
It does include a number of other changes related to the resizing of widgets. However if you only want then IE8 changes then I suppose the best answer is to search it for mention of ie8compat.
At the time of writing the line changes for ie8 are :
- 717 : Added IE8 compatibility option
- 2054 - 2056 : Added the .toggle option to the preview widget
- 2433 - 2435 : Added the .toggle option to any widgets moved up
- 2488 - 2490 : Added the .toggle option to any widgets moved down