I'm trying to create a alert using jQuery. But the problem is it is not a blocking call. I need to call this in a loop after checking some cases. If the user has entered some wrong content at first though a text essay, i need to present user to fix one line after checking errors.
Is there any way to block coding without using while loops or anything.
There is no way in JavaScript to make a blocking call. There is no wait()/sleep() in JavaScript. You need to break up the logic into two steps.
Related
I ran in the following problem while implementing show/hide of a div in my html.
This show/hide is governed by a variable say id, which I am storing and retrieving using session objects (using sessionAware in Struts 2).
My problem is following, even though I see that id variable is properly set in Java end, it is not working in JavaScript part.
On introducing the alerts around the reading of id variable is script, this works fine.
Can someone help me how to get rid of this problem?
Thanks in Advance!
It look like data load issue.
I assume like when you check for the value data is not loaded, and the check fails.
When you put an alert into it, the page pauses on alert, during that time the data loads and then you get it correctly then.
It is only an assumption based on what you provided.
Please provide some sample code or snipets.
There are a few functions that stop the code from running when they are called. This are called synchronous functions causing a pause in the code until you click OK. alert() is synchronous and so is prompt().
Till that time your data may be loaded, It my just opinion on the base of desc given.
regards,
I am trying to post some data to another php file using ajax. This data is on the link attribute. I am thinking bad guy on the page could inspect the element and change the value of that particular data attribute which i want to stop this from happening using javascript.
for example: <a href='#' data-user_id='25'> Add Friend </a>
How do i let javascript make sure the value of data-user_id still stand the same if a bad guy inspect the page and try to change the value of the attribute ??.
below is my code but its not working the way i want:
<script>
$(document).ready(function(e) {
$(".save").attr("data-user_id").change(function(){
var savefriendbtn = 57;
if($(".save").attr("data-user_id") !== savefriendbtn){
$(".save").attr("data-user_id","57");
}
})
});
</script>
A code example would be much appreciated.
Thank you
Short answer you can't verify the change, even if its doable what prevent the user from inspecting your JavaScript and play or monkey-patch some other code and override your client-side checks,
Client-side checks was never a way to verify valid data, its a way to help but you can't guarantee or depend on it, you should have a back-end validation for this parts of code,
Validate in back-end if this user is not permitted to add this user as a friend, otherwise no issue if he changed the id and add another one as long as he can do that, and you may or may not handle error for this part as actually for me i don't care if an error explode to user if its his fault by hacking.
If I am understanding correctly you need this function to run while the user (or bad guy) browses the page, constantly forcing the id of the element to be 57.
If I am not wrong you wouldn't need jquery.
There are two problems:
var savefriendbtn has a number type, 57, whereas you are setting it as "57", a string.
The problem should be because Document.ready only calls once, i.e. when the page loads for the first time. Hence, you would have set up an event listener or do as follows:
setInterval(function(){document.getElementById('save').data-user_id=57;},1000)
Does it help?
Then and again, the bad guy could simply change the var to another value, preventing the entire mechanism from working. I really hope this helps you.
Alright lets see if I can describe this.
I have a handful of functionality that was created sometime ago, and works swimmingly. However there is a new desired spec, so without having to rewrite the code base in a matter of speaking, and without having to double up on code to pull the same effect off I am trying to figure out how I can go about making something jump back higher in the code within the same function to repeat the run of the function rather then doing the same code again below.
What I have is a click based triggers ie:
$('.selector').click(function(){});
In this function is about 30 lines of functionality to create a new element and populate it accordingly. However unfortunately in that same bit of functionality there is conditions to wether it should or not.*The previous requirement was when the element it creates is open and populated just throw an alert() saying essentially wrap up what your doing, and then go on to the next. *Now the new requirement is just close that and open a new element. Which I've gotten to close out the existing, and do everything I want it to do, except the population of the new element which is above where the condition is currently. Knowing there is no "go to" type of logic in javascript (or last I knew). the only thing I can think of is taking the same code from above and putting it in the condition as well, doubling up on the code and having litterally 2 copies of the same bit. I want to avoid that, but cant think of a way to do it. So here I am looking for ideas
Knowing there is no "go to" type of logic in javascript (or last I
knew). the only thing I can think of is taking the same code from
above and putting it in the condition as well, doubling up on the code
and having litterally 2 copies of the same bit. I want to avoid that,
but cant think of a way to do it. So here I am looking for ideas
Why don't you just pull this piece of code out into a function? You can run the function if the conditional is true in the original instance, and run it all the time in your callback? This is fairly minimal refactoring, just move the code out of the logic into a separate function, keeping it as is and maybe making some of the referenced variables into parameters.
So something like this if you want to run all the actions regardless of the conditional statements:
...
if(condition){
actionA();
}
if(condition2){
actionB();
}
...
$('.selector').click(function(){
actionA();
actionB();
});
You're familiar with that pattern, right?
var aCallback = function(){........};
$('.selector').click(aCallback);
Been looking for hours. At https://stackoverflow.com/questions/ask how does the "Tags" section make the blue boxes appear below?
I don't think they are using keyup event trigger, since the blue boxes are not being updated on every keypress.
You can test this by going to https://stackoverflow.com/questions/ask and typing:
"aadfadasdfasdfasdfasdfasfasdfsaf"
As you type, you will notice that the blue box "aadfadasdfasdfasdfasdfasfasdfsaf" will only appear a few seconds AFTER typing. Not during.
They probably call setTimeout and clearTimeout to run their code 1 second after the last keyup event.
It's just a case of autocomplete. There are many ways of accomplishing this.
One way is to store the list of words to autocomplete on the client end. This is very fast and there won't be any delay (unless you program one in).
The other way is to make an AJAX call to the server and have it return a list of autocomplete words. This is how SO does it. Since you don't want to make an ajax call every time the user types in a letter, there is a delay implemented to save bandwidth and improve performance.
If you want to implement a similar feature on your own website, I suggest looking into jQuery plugins to achieve this as there are many freely available ones out there.
EDIT: The trigger is likely a keyup event as you mentioned. However the trigger will likely wait for a second or so using setTimeout() before showing the list of possible autocompletes. clearTimeout() is used if another key has been pressed during the delay to prevent multiple calls from being made.
Check out the source code using Firebug or another web inspector. You'll see that there's a file called full.js. It's minimized, but you can expand the code using a variety of online tools; I go the very lazy approach of copying/pasting the whole thing into the "javascript" box in jsfiddle and hitting "tidy". I'm sure there are better (and faster) ways to do it.
Anyway, in that file, there are a few functions that may interest you: StackExchange.tagPreferences and it's subfunctions, initTagRenderer, and StackExchange.inlineEditing. I think the last function is the one that causes the specific delay you're referring to, but it's pretty hard to tell.
When I use AJAX for part of my page, such as a commentbox, in the reloaded box no JavaScript works. e.g. like cutetime or whatever. So I guess I have to reload the cutetime command (in every reload of the commentbox)
It works, but I think I have the cutetime command twice. If I have a confirm box or anything other, I get the confirm box or the add command twice.
I'll try to describe it in one sentence:
I need a way to get JavaScript working in a reloaded AJAX-Box.
P.S.: I think there is a very easy way because everybody uses it :)
If you replace an element anything attached to it is lost.
When using jQuery, you can avoid this issue by using live events. However, this doesn't work for plugins where you don't attach events. In that case you need to call whatever function enables something on your element again when replacing it.