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

Javascript Uncaught TypeError: Cannot read property ‘0’ of undefined

The error is here: You are passing the first item of words, instead of the array. Instead, pass the array to the function: Problem solved! Here’s a breakdown of what the problem was: I’m guessing in your browser (chrome throws a different error), words[] == words[0], so when you call hasLetter(“a”,words[]);, you are actually calling hasLetter(“a”,words[0]);. So, in essence, … Read more

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

Current time formatting with Javascript

A JavaScript Date has several methods allowing you to extract its parts: getFullYear() – Returns the 4-digit yeargetMonth() – Returns a zero-based integer (0-11) representing the month of the year.getDate() – Returns the day of the month (1-31).getDay() – Returns the day of the week (0-6). 0 is Sunday, 6 is Saturday.getHours() – Returns the hour of the day (0-23).getMinutes() – … 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

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