I am in need of a JavaScript function which can take a value and pad it to a given length (I need spaces, but anything would do). I found this, but I have no idea what the heck it is doing and it doesn’t seem to work for me. Answer ECMAScript 2017 (ES8) added String.padStart (along with String.padEnd) f…
Is there a way to check if a var is using setInterval()?
For instance, I am setting an interval like and if i go and do it does clear the interval but is there a way to check that it cleared the interval? I’ve tried getting the value of it while it has an interval and when it doesn’t but they both just seem to be numbers. Answer There is no direct
Check if dropdown’s selected option is not the first with JavaScript
Below are the options that I have in my HTML code: I want to create JavaScript code that will check whether the user selected an option other than the first one. Here is what I tried: Answer You can check like this if nothing is the first option (usually the case in my experience): To still compare based on t…
How can I determine if a variable is ‘undefined’ or ‘null’?
How do I determine if variable is undefined or null? My code is as follows: But if I do this, the JavaScript interpreter halts execution. Answer You can use the qualities of the abstract equality operator to do this: Because null == undefined is true, the above code will catch both null and undefined.
After travelling back in Firefox history, JavaScript won’t run
When I use the back button on Firefox to reach a previously visited page, scripts on that page won’t run again. Is there any fix/workaround to have the scripts execute again when viewing the page the second time? Please note that I have tested the same pages on Google Chrome and Internet Explorer and th…
Why JavaScript IF only works once?
I have JavaScript code which copies the value of input file and paste it in the text box in real time. Sadly this only works once and then stops pasting the value when changing the file again. (I mean you should reload the page to make it work again) Does IF have a cache or something? You can try the
Avoid browser popup blockers
I’m developing an OAuth authentication flow purely in JavaScript and I want to show the user the “grant access” window in a popup, but it gets blocked. How can I prevent pop up windows created by either window.open or window.showModalDialog from being blocked by the different browsers’…
Is ternary operator, if-else or logical OR faster in javascript?
Which method is faster or more responsive in javascript, if-else, the ternary operator or logical OR? Which is advisable to use, for what reasons? Answer The speed difference will be negligible – use whichever you find to be more readable. In other words I highly doubt that a bottleneck in your code wil…
Assign variable in if condition statement, good practice or not? [closed]
Closed. This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 3 years ago. Improve this question I moved one years ago from classic OO languages such like Java to Jav…
How can I tell when changes to jquery html() have finished?
I’m using jQuery to change the HTML of a tag, and the new HTML can be a very long string. $(“#divToChange”).html(newHTML); I then want to select elements created in the new HTML, but if I put the code immediately following the above line it seems to create a race condition with a long string…