Techniques and Web Technologies
Content of HTML table cells can be dragged to another cell or another table. It isn’t difficult to define onMouseMove handler and change top / left element styles to move the object. In case with tables, you will have to determine somehow destination cell. Attaching onMouseOver handler on TD elements will not work, because browser doesn’t fire events to the elements beneath the dragged object.
REDIPS.drag is a JavaScript drag and drop library focused on dragging table content and table rows. Here you will see a list of public properties and methods contained in REDIPS.drag library. Documentation is generated with JsDoc Toolkit.
REDIPS.drag was initially built to drag and drop table content. After publishing first version of REDIPS.drag, I received a lot of questions about dragging table rows also. Now is possible to drag and drop table rows as well as table content.
School timetable is example of how to use REDIPS.drag library. Page layout contains two tables – left table with school subjects and timetable on the right. After subject is placed to timetable, button in the same color will be displayed next to the subject (clone object).
With insertRow() method you can insert a new row at the specified position in HTML table. After row is created, use insertCell() method to insert a table cell. Wrap this methods in JavaScript functions and you have code to dynamically add new rows and columns in the HTML table.
JavaScript date validation can be done in many ways like month range testing, day range testing (depending on number of days in the month) and so on. Here is shown much simpler solution. Take day, month and year from input string to create JavaScript Date object. Compare input day, month and year with day, month and year extracted from the Date() object. If they aren’t the same then the input date is not valid.
If prompt, confirm, alert or window.open are not good enough then JavaScript dialog box can be considered as an alternative choice. This dialog box is emulated with two DIV elements. First DIV overlays whole page while second DIV is positioned at the page center. That’s nothing new but JavaScript code is short, well commented and closed in its own namespace.
With few lines of JavaScript and CSS it’s possible to make simple AJAX progress bar. JavaScript will periodically ask for progress value and server will respond with JSON data. Progress value is being read and displayed as DIV element width. To start progress bar demo, click on Start button and wait few seconds to begin. To watch how this page sends requests to Web server just open DOM inspector “Network” card.
Here is list of keywords (mostly class names) used in REDIPS.drag library. Id of drag container(s) or table cell class names should be named properly to achieve needed functionality like cloning DIV elements, adding trash cell, mark cells, adding row handler or mark table as “nolayout”. This post is appendix to the REDIPS.drag documentation post.
REDIPS.table is small JavaScript library which enables interactive or through script merging and splitting table cells. REDIPS.table.onMouseDown() public method will activate onMouseDown event listeners on TD elements to enable mark cells with mouse button. Additional feature is appending / deleting table rows / cells.
This post shows two examples of how to find the week list for the current date. Input parameter is date, and the output is date list from Monday till Sunday. First example is done with classic algorithm while second example uses ISO week date format.
This post describes how to maintain vertical scroll position after form submission or clicking on link. Script will read vertical scroll position and append scroll value to URL. After page is loaded, JavaScript function will search for scroll parameter in URL and set the scroll position.