Using javascript to avoid the mouse and page scrolling

Here's the problem. It is not very easy to scroll a document when you're inside an input element. Arrow keys don't work, and Page Up/Page Down jump in big increments. What if you want to see just a few lines below the current element? Our clients hate to scroll. And they hate having to use the mouse. This just brings the two together.

FScroll is a JQuery plug-in which makes a page scroll to the currently focussed element, keeping it's position centered with respect to the document. This helps keep a bit of "context" around the currently focussed element - since it is centered, you can see a few elements both above and below the currently focussed element.

Here are the sources. And here's a page explaining it's usage in some detail. And oh, it does nested centering too. But it requires that the 'nesting' container have a css styling of position : relative (in the demo page, the div enclosing the table is positioned relative). This was not strictly necessary, but it made the coding a bit easier. If you can't live with the styling restriction, let me know. I'll try to do what I can.

You may report issues here.

`calculable' textboxes using jquery

Here's some code to make your textboxes calculable. Demonstration here.

(function($) {
            $.fn.calculable = function() {
                return this.each(function() {
                    $(this).focus(function(e) {
                        var expr = $(this).attr('calcExpr');
                        if (expr) {
                            $(this).val(expr);
                        }
                    }); // end focus
                    
                    $(this).blur(function(e) {
                        try {
                            var expr = $(this).val();
                            var calculated = eval('with(Math){'+expr+'}');

                            $(this).attr('calcExpr', expr);
                            $(this).val(calculated);
                        }
                        catch (e) {
                            $(this).attr('calcExpr', '');
                        }
                    }); // end blur
                }); // end each
            };
        })(jQuery);

Yes, it uses eval. Doesn't evaluate on initial load. Provides no way to post the expression to the backend.

Expect improvements, and submit patches, once this goes into source control.

edit: Now available in a github repository.