When and why to ‘return false’ in JavaScript?
Often, in event handlers, such as onsubmit, returning false is a way to tell the event to not actually fire. So, say, in the onsubmit case, this would mean that the form is not submitted.
javascript
Using Javascript in CSS
IE and Firefox both contain ways to execute JavaScript from CSS. As Paolo mentions, one way in IE is the expression technique, but there’s also the more obscure HTC behavior, in which a seperate XML that contains your script is loaded via CSS. A similar technique for Firefox exists, using XBL. These techniques don’t exectue JavaScript from CSS directly, but … Read more
Adding options to select with javascript
You could achieve this with a simple for loop: JS Fiddle demo. JS Perf comparison of both mine and Sime Vidas’ answer, run because I thought his looked a little more understandable/intuitive than mine and I wondered how that would translate into implementation. According to Chromium 14/Ubuntu 11.04 mine is somewhat faster, other browsers/platforms are likely to have differing … Read more
How to specify multiple conditions in an if statement in javascript
just add them within the main bracket of the if statement like Logically this can be rewritten in a better way too! This has exactly the same meaning
jQuery AJAX cross domain
Use JSONP. jQuery: PHP: The echo might be wrong, it’s been a while since I’ve used php. In any case you need to output callbackName(‘jsonString’) notice the quotes. jQuery will pass it’s own callback name, so you need to get that from the GET params. And as Stefan Kendall posted, $.getJSON() is a shorthand method, but then you need to … Read more
React eslint error missing in props validation
You need to define propTypes as a static getter if you want it inside the class declaration: If you want to define it as an object, you need to define it outside the class, like this: Also it’s better if you import prop types from prop-types, not react, otherwise you’ll see warnings in console (as preparation for React 16):
Firebase Permission Denied
By default the database in a project in the Firebase Console is only readable/writeable by administrative users (e.g. in Cloud Functions, or processes that use an Admin SDK). Users of the regular client-side SDKs can’t access the database, unless you change the server-side security rules. You can change the rules so that the database is only readable/writeable … Read more
How to pass props to {this.props.children}
Cloning children with new props You can use React.Children to iterate over the children, and then clone each element with new props (shallow merged) using React.cloneElement. For example: Calling children as a function Alternatively, you can pass props to children with render props. In this approach, the children (which can be children or any other prop name) is a function which … Read more
Unable to verify leaf signature
Note: the following is dangerous, and will allow API content to be intercepted and modified between the client and the server. This also worked process.env[‘NODE_TLS_REJECT_UNAUTHORIZED’] = ‘0’;
Uncaught TypeError: $.post is not a function
You are using the slim version of jQuery, which doesn’t include the Ajax methods (in your case $.post()). Use the non-slim build, available here http://jquery.com/download/, such as: https://code.jquery.com/jquery-3.5.1.min.js From jQuery 3.0 release post: Slim build […] Sometimes you don’t need ajax, or you prefer to use one of the many standalone libraries that focus on ajax requests.[…] Along with the regular version of … Read more