javascript - Read For Learn

jQuery.click() vs onClick

Using $(‘#myDiv’).click(function(){ is better as it follows standard event registration model. (jQuery internally uses addEventListener and attachEvent). Basically registering an event in modern way is the unobtrusive way of handling events. Also to register more than one event listener for the target you can call addEventListener() for the same target. http://jsfiddle.net/aj55x/1/ Why use addEventListener? (From MDN) addEventListener is the way to register an event listener as specified in W3C DOM. Its … Read more

How can you encode a string to Base64 in JavaScript?

You can use btoa() and atob() to convert to and from base64 encoding. There appears to be some confusion in the comments regarding what these functions accept/return, so… btoa() accepts a “string” where each character represents an 8-bit byte – if you pass a string containing characters that can’t be represented in 8 bits, it will probably break. This isn’t a … Read more

Reactjs – Form input validation

You should avoid using refs, you can do it with onChange function. On every change, update the state for the changed field. Then you can easily check if that field is empty or whatever else you want. You could do something as follows : In this example I did the validation only for email and name, but … Read more

I am getting an “Invalid Host header” message when connecting to webpack-dev-server remotely

I found out, that I need to set the public property of devServer, to my request’s host value. Being that it will be displayed at that external address. So I needed this in my webpack.config.js Another solution is using it on the CLI:

JavaScript getElementByName doesn’t work

It’s getElementsByName . Note the plural. It returns an array-like NodeList of elements with that name attribute.

How can I scroll to an element using jQuery?

JavaScript answer If you would like to scroll to an element smoothly with “pure JavaScript” you could do something like this: More information is here: Element.scrollIntoView() NOTE: Please see Can I use… Support tables for HTML5, CSS3, etc. for the latest browser support… jQuery answer If you would like to scroll to an element smoothly using jQuery then … Read more

How to disable JavaScript in Chrome Developer Tools?

Update August 2020 Developer Tools (F12) Click the Gear icon Should open the Preference tab Disable Javascript option is on the far right Original answer Developer Tools (F12) Three vertical dots in upper right Settings Under the “Preferences” tab on the left There will be a “Debugger” section with the option (probably on far right)

What is the way of declaring an array in JavaScript?

The preferred way is to always use the literal syntax with square brackets; its behaviour is predictable for any number of items, unlike Array‘s. What’s more, Array is not a keyword, and although it is not a realistic situation, someone could easily overwrite it: However, the larger issue is that of consistency. Someone refactoring code could come across … Read more

Node.js heap out of memory

If I remember correctly, there is a strict standard limit for the memory usage in V8 of around 1.7 GB, if you do not increase it manually. In one of our products we followed this solution in our deploy script: There would also be a new space command but as I read here: a-tour-of-v8-garbage-collection the new space … Read more

How to deal with net::ERR_SSL_PROTOCOL_ERROR?

This is not a javascript problem, it’s an ssl probem. You can’t get a file through an insecure connection (http) from a html page served through a secure connection (https). If you’re going to use https (and you SHOULD!) then you need to get the script through a secure connection. To get the file, you … Read more

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