It is generally discouraged to load your JavaScript by a tag in the : The reason is that a tag will pause the DOM parser until the script has loaded and executed. This will delay the browser's first contentful paint. A much better default is to load your scripts with a tag: A deferred script has many...
This bookmarklet grabs a PivotalTracker story title, transforms it into a valid git branch name and automatically prepends your initials...
The attached compiler() function below applies JavaScript behavior to matching HTML elements as they enter the DOM. This works like...
Given you have a strict CSP that only allows elements from your own domain: Content-Security-Policy: script-src 'self' This will block JavaScript handlers inlined as attribute into your HTML elements. Clicking on the following link will only log an error with a strict CSP: click me click me Solution 1: Move the handler into your JavaScript The recommended solution is to move the handler from the HTML to the allowed JavaScript file that we loaded via . In the example above we could invent a new [data-alert] attribute with the alert message: click me Then our JavaScript intercepts clicks on elements with that attribute: document.addEventListener('click', function(event) { let link = event.target.closest('[data-alert]') if (link) { let message = link.dataset.alert alert(message) event.preventDefault() } }) Solution 2: Allow that one handler in your CSP Some browsers allow the CSP directive script-src-attr. This lets you allow the hashes of actual JavaScript code. The SHA256 hash of alert('hello') is vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE= (in Base64). We can allow this one event handlers like this: Content-Security-Policy: script-src 'self'; script-src-attr 'unsafe-hashes' 'sha256-vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE=' Note the sha256- prefix. This event handler now works when clicked: click me But any other script will still be blocked: click me Dealing with legacy browsers Currently (November 2023) about 75% of browsers support script-src-attr. Here is a forward-looking compromise that many users use with new CSP features: Have a liberal CSP with old directives supported by all browsers Make your CSP stricter with new, more specific directives for browsers that support it The CSP spec supports that approach in that using newer, more specific directives disable older, more general features. In our case this means: For old browsers, allow all inline scripts For new browsers, disallow inline scripts but allow inline handlers with given hashes Here is a CSP directive that works like this: Content-Security-Policy: script-src 'self' 'unsafe-inline'; script-src-elem 'self'; script-src-attr 'unsafe-hashes' 'sha256-vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE=' Old browsers will only use script-src. New browsers will use script-src-elem (for tags) and script-src-attr (for inline event handlers), which override the more liberal rules from script-src.
Often people need links which are not linked directly, but should trigger execution of JavaScript. ❌ Bad workarounds
If you want to expand your Areca Raid by swapping out the disks for larger ones you will need to...
You can scale background images in CSS to the container size using background-size (Demo). Commonly, we use contain or...
You can throttle the network in your headless chrome via Selenium. This might be useful for debugging issues with flaky...
What is netfilter's Connection Tracking system? The connection tracking system often referenced as nf_conntrack is part of the...
When testing JavaScript functionality in Selenium (E2E), you may need to access a class or function inside of a evaluate...
I encountered a unlucky behavior of byebug 11.1.3 (the most recent version at time of writing) when using it with...
Browsers usually cache website content in order to provide the user with faster responses. Examples are returning to a website...
When a Ruby version gem has a letter in its version number, it is considered a pre-release:
Webpack builds can take a long time, so we only want to compile when needed. This card shows what will...
When you need the DOM node of a tag (e.g. to read extra attributes, or to modify the DOM near it), you can usually reference it via document.currentScript. However, document.currentScript is unsupported in ancient browsers, like Internet Explorer 11 or wkhtmltopdf's Webkit engine. If you are not running async scripts, you can easily polyfill it: document.scripts[document.scripts.length - 1] It works because document.scripts grows with each tag that was evaluated. That is also the reason why this solution will not work reliably for async code. Demo: https://codepen.io/foobear/pen/poRLxQm
I use the TypeScript compiler for this, since its output is more minimal than Babel's. The following will transpile...
When your Rails application server raises error, Capybara will fail your test when it clears the session after the last...
Browsers blocks abusable JavaScript API calls until the user has interacted with the document. Examples would be opening new tab...
In Ruby (almost) everything is an Object. While this enables a lot of powerful features, this concept might be confusing...
capybara-lockstep can help you with flaky end-to-end tests: This Ruby gem synchronizes Capybara commands with client-side...
json is part of the standard library of Ruby and deals with JSON, obviously. As you know, JSON is the...
If your project depends on an old version of ImageMagick that you can no longer install in your system, you...
When you repeat a subpattern with a *, + or {...} operator, you may choose between greedy, lazy and possessive modes. Switching modes...
Rails 6 includes a WYSIWYG editor, Action Text. It works out of the box quite well, but chances are that...