I understand that I currently can't use <a onclick="alert('<%=TextBox1.ClientID%>')" directly because I need to access it in a table cell in a table in the EditTemplate of a DataList inside a UserControl.
That said, I need to recursively check the controls to get the ClientID, should it be done
client-side: alert(getMyElement('TextBox1').id), where getMyElement checks all elements of the form and returns the control with the id...or
server-side: alert('<%=FindElement(dlDataList, "TextBox1").ClientID%>') where FindElement is a base page function that checks the controls of the first param for an element with an id of the second param and returns that control
?
I'm figuring the client-side would be faster?
I always go with server side for this case. Otherwise you're traversing the entire DOM with each row - depending on the size, it could be a memory hog. Server side takes almost no resources for this.
Related
I have a listing page for an e-commerce website with various items (item_list.php). This page is generated with a PHP loop and displays each item inside a <li> element. Every item is a link to the same page, called item_details.php .
When clicking on the link i want to run a script that changes a SESSION var to a certain $id (which will be excracted from the <li> itself with .innerHTML function) and then allowing the browser to move into the next page (item_details).
This is needed so i can display the proper information about each item.
I think this is possible with Ajax but I would prefer a solution that uses JS and PHP only.
(P.S.This is for a University project and im still a PHP newbie, i tried searching for an answer for a good while but couldn't find a solution)
No JS or other client-side code can set session values, so you need either an ajax call to php, or some workaround. This is not a complete answer, but something to get you thinking and hopefully going on the project again.
The obvious answer is just include it in the link and then get it in PHP from the $_GET -array, and filter it properly.
item title
If, however, there is some reason this is not a question with an obvious answer:
1.) Closest what you're after can be achieved with a callback and an ajax call. The idea is to have the actual link with a click function, returning false so the link doesn't fire at once, which also calls an ajax post request which finally will use document.location to redirect your browser.
I strongly advice against this, as this will prevent ctrl-clicks causing a flawed user experience.
Check out some code an examples here, which you could modify. You will also need an ajax.php file which will actually set the session value. https://developers.google.com/analytics/devguides/collection/analyticsjs/enhanced-ecommerce#product-click
2.) Now, a perhaps slightly better approach, if you truly need to do this client-side could be to use an click handler which instead of performing an ajax call or setting session directly, would be to use jQuery to set a cookie and then access this data on the item_list.php -page.
See more information and instructions here: https://www.electrictoolbox.com/jquery-cookies/
<script>
$('product_li a).click(function(){
$.cookie("li_click_data", $(this).parent().innerhtml());
return true;
});
</script>
......
<li class="product_li">your product title</li>
And in your target php file you check for the cookie. Remember, that this cookie can be set to anything, so never ever trust user data. Test and filter it in order to make sure your code is not compromised. I don't know what you want to do with this data.
$_COOKIE['li_click_data'];
3.) Finally, as the best approach, you should look at your current code, and see if there is something you can re-engineer. Here's a quick example.
You could do the following in php to save an array of the values in the session on each page load, and then get that value provided you have some kind of id or other usable identifier for your items:
// for list_items.php
foreach($item as $i) {
// Do what you normally do, but also set an array in the session.
// Presuming you have an id or some other means (here as item_id), to identify
// an item, then you can also access this array on the item_details -page.
$_SESSION['mystic_item_data_array'][$i['item_id]] = $i['thedata'];
}
// For item_details.php
$item_id = // whatever means you use to identify items, get that id.
$data_you_need = $_SESSION['mystic_item_data_array'][$item_id];
Finally.
All above ways are usable for small data like previous page, filters, keys and similar.
Basically, 1 and 2 (client-side) should only be used, if the data is actually generated client-side. If you have it in PHP already, then process it in php as well.
If your intention is to store actual html, then just regenerate that again on the other page and use one of the above ways to store the small data in case you need that.
I hope this gets you going and at least thinking of how to solve your project. Good luck!
In general we call the jqgrid as in$("#grid_loc").jqGrid({});
But i want to specify the context like $("#grid_loc",context).jqGrid({}). But this is not working. Can somebody help in this?
I have to load server side data using url option.
Infact i occured to have this, as i have tabs on my page.
In each tab, i have to have a jqgrid, not different grids but same grid with different data .
Here i am getting the tab context using var tabset = $("div.tabset");
newdivid = $("div[class*='active_tab']",tabset).attr("id");
var newmenudivid = $("#"+newdivid);
And
the grid code as
$("#grid_workflow", newmenudivid).jqGrid({....});
I have been trying to find out a way to do this. you can find some of my effort in the comments section of the link
how to develop same jqgrid in multiple tabs
i was successful with id overwriting for the same purpose. But that is not a good way though. So i am forced to have another approach ie. context
I suppose that you misunderstand some important things which corresponds to id attribute. The most important that all elements on the page having id attribute have to have unique value of the attribute. In other words the ids have to be unique over the whole HTML page.
So if you need create for example tree grids inside of tree tabs you have to define different id attributes for every grid. For example; grid_workflow1, grid_workflow2, grid_workflow3. If you create the tabs and grids dynamically then you can have some variable in the outer scope (for example global variable) and increase the value of the variable. You can construct id of the grid using some prefix (like "grid_workflow") and the value of the variable. In the way you can create multiple grids with unique ids. Many JavaScript libraries uses the way to generate unique id attribute. Ij you want you can use $.jgrid.randId() method which will returns you unique strings which can be used as ids.
Because of the syntax $("#grid_workflow", newmenudivid) you should understand one important thing. I would recommend never use it. The reason is very easy. It could help only if you have id duplicates. In all other cases if will works exactly like $("#grid_workflow") but slowly. The reason is easy to understand. Web browser hold internally the list if all ids on the page and if you use getElementById method directly of indirectly (in $("#grid_workflow")) the searching of the element with the required id will be like searching in the index in the database. So you will have best performance results. If you use $("#grid_workflow", newmenudivid) then you don't allow web browser to use the index of elements by id. So the usage of context will follow to slow searching throw all children elements of newmenudivid. So you should avoid usage of jQuery context with id selectors.
Is there an existing library that would do this?
I want to be able to have code on the client side where the user chooses something, it makes a call to the server, and the server sends back "for this option, you need a have a text field called foo and a select field called bar with the following options, this one is selected, etc", and then the client side builds the next part of the form from that information. Or if they choose a different option, a different set of fields and values is returned from the server and populated on the screen. Also it might cascade so after the first selection we need a select field with some options, and then depending what they select on that select field the next field might be another select field or it might be a text input field.
Has anybody done anything like that? Is my best choice to have the AJAX call return some html that I just stuff into a div, or can I do it field by field and value by value?
If it matters, the back end is going to be written in Perl/MASON, and the front end will be using Javascript/JQuery/JQuery-UI.
I would use jquery and submit AJAX calls to whatever backend system you choose. Have this backend system compute the necessary changes and return the info as JSON. Let JQuery parse it for you and append the necessary form elements. However, it seems like under alot of use cases these decisions could be made on the client side without even talking to the server just as we pre validate form input before allowing posting to the server. I don't, however, have your requirements in front of me so I am sure there is a reason you want to get the info back from the server.
P.S. please do not return pure html from the back end to the client....ever.
I have a form where user is able to choose search options. When user clicks "Search" button,
an appropriate GET controller's action is invoked:
public ActionResult Search(SearcherViewModel model, int pageNo=1)
{
var results = xService.GetSearchResults(model);
return View("Index", results);
}
GetSearchResults method does not connect to the database, but instead it call some third party web service. This however is not the main issue.
Therefore, the url can look as follows:
http://localhost/Search?startDate=20120210&offerType=3&foodId=4&&Destination=456
How can I implement a pagination of search results? In particular, how should I construct the page numbers and how to use my model?
Kinda depends on how much stuff you are paginating. If it is small then you can hold the whole thing in javascript memory using preloading and then paginate based on the javascript objects. If you are looking at potentially tens of thousands or more of items to paginate, then you may consider preloading part of that and then using ajax to load pages later on depending on how the user navigates.
I've been having a look at several MVC frameworks (like rails, merb, cakephp, codeignitier, and similars...)
All the samples I've seen are basically plain and simple CRUD pages, carrying all the infr needed in the querystring and the posted field values.
I've got a couple of apps made with some sort of framework built with classic asp.
This framework handles some CRUD stuff a little more complex than the examples I found.
Something like master-detail, filtering by example, paging, sorting and similars.
I have a controller class that it's just a finite state machine, that goes thru diferent states (like new, browse, filter, show, etc.), then performs the appropiate action depending on the event raised and finally retrieves the neede info to the calling page.
To achieve this I have several hidden inputs to keep the state of the web page (like current id, filter criterias, order criterias, previous state, previous event, well, you get the idea)
What do you think would be the finnest approach to achieve this kind of funcionality?
hidden inputs built in the view and used from the controller??? (I guess that would be the equivalent of what I'm doing right now in classi asp)
--
(added in response to tvanfosson)
basically, my question refers to the third category, the context-dependent setting (in respect to the other two categories I agree with you) the info I was storing in hidden fields to store them on the querystring, I guess that when you click on the "next page" you include everything you need to save in the querystring, right? so that piece of query string gets appended in each and every link that performns some kind of action...
I'm not sure, what are the advantages and disadvantages of using the querystring instead of hidden inputs???
I use different strategies depending on the character of the actual data. Things that are preferences, like default page size, I keep in a Preferences object (table) that is associated with the current logged in user and retrieve from there when needed.
Persistent settings associated with the current logon, like filter settings for a page, are stored in the user's session. Generally these are things that if a user sets them in the current session they should remain sticky. I think filter settings and visibility are like this. If I filter a list, navigate away from it to drill down into a particular item, then come back to the list, I want my filter settings to be reapplied -- so I make it part of the session.
Context-dependent settings -- like the current sort column or page number, are controlled using query parameters. Paging and sort controls (links) are built with the appropriate query parameters to "do the right thing" when clicked and pass any necessary query parameters to maintain or update the current context of the control. Using the query parameters allows you to use an HTTP GET, which is bookmarkable, rather than a POST. Using hidden form parameters makes it much harder for the user to save or enter a URL that takes them directly where they want to go. This is probably more useful for sorting than it is for paging, but the principle applies equally.