I was wondering if I could get a little bit of guidance with Javascript. This is all going to be from scratch so no frameworks or plug-ins involved.
I'm starting a new project where I'll have a page with 12 thumbs and a next button. Clicking the next button, slides the 12 thumbs to the left and hides them, showing 12 more thumbs which will be added to the DOM on the fly, etc etc. Once you're on page 2 or above, a previous button will be displayed. All of the info that will be used to populate the DOM I imagine will be in the form of JSON. Is that the best way? Would an array suffice? What is the best way to keep track of what page I'm on? When I'm on page 2, what is the best way to get items 13-24 from the JSON object, etc?
I have some ideas but I'm looking for best practices.
Use objects inside an array, with each object containing the info such as thumb path, image path, caption, etc.
You can slice() an array.
However, if using JSON, you probably want to request with XHR the images as you want them, so just pass the page number and your server side code can calculate the offsets.
Related
I want my blog to be more interesting by making it different every time a reader reads a post. For example, I want to tell a story using a quote from a famous person, a picture, and a situation from the real life. Say, I have 2 relevant quotes, 3 pictures, and 10 situations to use. I don’t want to use them all together, instead, I want every item to be randomly selected during the page load, this will give me 2×3×10 = 60 different variants of the page. If I had a database-backed site, I would select them parts from a DB, but I like the Middleman much and the page must be static.
What would you recommend?
JQuery might be the lightest weight easy solution here. You could use JavaScript to randomly choose each element and place them on the screen.
If you wanted to make sure the person had a unique message each time, you could record the selected combination in a client side cookie so on subsequent visits, your code checks the cookie to make sure that the combination is different than the previous x number of visits.
Depending on how long those 10 stories are, I would say maybe the quotes and the stories could be downloaded as a compressed JavaScript file that contains the list in a JSON. When you set the img src attribute using JQuery, it should pull the required image down from the server.
It would be a small project for me to show you all the details here but hopefully I've given you enough information to help you get started. You may have to use Google to fill in for examples of random numbers in JavaScript, using cookies with JQuery, replace image using JQuery.
I have a use case where there are thousands of items on a list shown to the user. They are loaded a small batch at a time and I see the network traffic going in and out, I see data getting loaded. I see the DOM getting bigger, but the list itself in the UI stops updating (Chrome).
When I examine it, I see thousands of items in the code, when I select the items through console and make it count them, I see the proper number. But in the page itself, I don't see these items get displayed. The list uses drag-and-drop to put items from it into another list (and load additional data about them).
Not using jquery.datatables at the moment, but been meaning to migrate to them a long time ago. I can’t find a good example, though, everything I see uses pagination to split, but what if this is not an option?
How can I pinpoint what it is that is preventing the items from display? The number of entries will vary between 500 and 20 000.
Never mind. everything works as intended, duh. I was stupid and missed something very obvious: things had "display: none" for a very good reason about which I totally forgot (has to do with the core logic of the application). Next time hit me with a stick so I could remember to pay more attention.
Not sure what you meant by saying 'DOM getting bigger' but 'don't see items get displayed'.
Typically JS has a main thread which will handle functions/callbacks as well as view-refresh. So if you operation is blocking , the view will not be refreshing.
As for the pagination is not an option thing, you can consider using DOM-lazy-Loading mechanism where you only put what should be in the current viewport into the dom. As user scroll, you calculate the scroll height dynamically to add/remove items to/from the DOM. One thing to remember is you typically need to define a fixed height for your rows so that you could do the calculation. This lazy-loading way is a common way of solving this type of problem and is widely used by different frameworks like GXT, angular-gird..etc.
I'm trying to make a page that allows users to select one shirt, one pair of pants, and a pair of shoes from an existing selection (horizontal scrollers for each group). The user then submits their selection and I receive an email of the users selection. Ideally the user should be able to see their complete selection either as an isolated element on the page or each scroller should focus on the chosen element.
I've been unsuccessful getting the selected element to display separately somewhere on the page.
As far as having three separate scrolling windows I was going to create three forms and put them in iframes, but it seems as though getting multiple forms to post with one submit button, and processing them is quite difficult.
I could scroll over all three groups simultaneously and this way keep it one form (shirts, pants, shoes) but this would be pretty ugly.
Here is a link to my scrolling form made from only one group. http://www.evan-livingston.com/test/list.php
I'm new to all of this, and I'll sacrifice some polish in order to get a working system.
What approach would be best to accomplish this system?
thanks in advance.
more elegant looking suggestion (using only client side programming)
use forms and create a table with each element as part of TD or inline list
on click--> highlight the image
on double click--> push/append it to a new div with info(link, name etc) about image and do the needful in the form of anchors and list tags
this new div can be displayed now or on a click of a submit button as a list of selected items. add an anchor to remove an item on click.
well there can be many ways to go about it. this is just one way and avoid the pain of using php.
since u asked about approaches: i prefer client side programming to php but thats purely based on my experience. use jquery to help u move around with js.
First off I'm open for suggestions of alternative ways of doing things.
To get going here is an image of what I want to achieve(kind of, sorry for the BAD paint job)
OK.. I have a request that gets fired off and sends back a ton of json containing information about Pupils Names, Sex, Age, Location.
I want to build a sort of table in the form of list elements, each tuple containing one unique student that the request returns.
I want to style it in a specific way, so it would appear as a row but each piece of data appears cellular, as in its a specific width with a border etc. As in each peice of data is a unique html element with a specific css style, but it appears to the user as a single row. (As in the 2nd and 3rd image in the drawing.)
Hovering over the data elements in a tuple(row) changes the hover state of all the cells in that row.
The end cell contains a plus..clicking this will update data in another div on the page. Whereas clicking the other cells in a row will take the person to another page related to that particular pupil.
Without using anything other than Javascript(librarys are okay i.e jQuery) and CSS how is the best way to go about this?
Is my thinking of how to do it okay or is there a better way?
Its also worth noting if my requests brings back 25 results, I only want to show 10 at a time but the person must be able to somehow view the remaining 15. How would I go about this also?
Thanks in advance.
I don't have the tools to test this at the moment, but it might work to set a hover property on the row-container, for example:
div.row:hover div.cell {
background: #006;
}
Or something like that.
For the part of your question about showing 10/25 elements...you could hide it with JavaScript and have a button to show them I guess, I'm not sure about why you are doing this. It might be better to implement something server-side if you want to paginate results.
I have some HTML documents that are converted to PDF, using software that renders using QtWebkit (not sure which version).
Currently, the documents have specific tags to split into columns and pages - so whenever the wording changes, it is a manual time-consuming process to move these tags so that the columns and pages fit.
Can anyone provide a way to have text auto-wrapped into the next column/page (as appropriate) when it reaches the bottom of the current container?
Any HTML, CSS or JS supported by QtWebkit is ok (assuming it works in the PDF converter).
(I have tested the webkit-column-* in CSS3 and it appears QtWebkit does not support this.)
To make things more exciting, it also needs to:
- put a header at the top of each page, with page X of Y numbering;
- if an odd number of pages, add a blank page at the end (with no header);
- have the ability to say "don't break inside this block" or "don't break after this header"
I have put some quick example initial markup and target markup to help explain what I'm trying to do.
(The actual documents are far more complicated than that, but I need a simple proof-of-concept before I attack the real ones.)
Any suggestions?
Update:
I've got a partially working solution using Aaron's "filling up" suggestion - I'll post more details in a bit.
Create a document with a single page and all the text in a single column. Use JavaScript to cut the text into parts.
Use pixel coordinates to locate the paragraph/element that doesn't fit anymore. Move it and everything below to the next col. If a "page" already has two "col" divs, start a new page.
After all pages have been created, count and number the pages. Fix even/odd stuff, etc.
Will take some time but it's automatic.
Another approach would be to add all the content to a "source" div and move items to the col div until it's full and repeat with the next col.
Have a look at Prototype or jQuery; they should give you lots of tools to move stuff around in the document.
[EDIT] Instead of only relying on jQuery functions, I suggest to create one or two objects which keep track of the current page and the current column, etc. These give you stable foundations to stand on from which you can fire the helper methods.