javascript
React – uncaught TypeError: Cannot read property ‘setState’ of undefined
This is due to this.delta not being bound to this. In order to bind set this.delta = this.delta.bind(this) in the constructor: Currently, you are calling bind. But bind returns a bound function. You need to set the function to its bound value.
Babel 7 – ReferenceError: regeneratorRuntime is not defined
Updated Answer: If you are using Babel 7.4.0 or newer, then @babel/polyfill has been deprecated. Instead, you will want to use the following at the top of your main js file (likely index.js or similar): Install these packages either with npm: or with yarn: Original Answer: I just encountered this problem and came across the … Read more
How do I check whether a checkbox is checked in jQuery?
This worked for me: Where isAgeSelected is the id of the control. Also, @karim79’s answer works fine. I am not sure what I missed at the time I tested it. Note, this is answer uses Microsoft Ajax, not jQuery
Remove class using jQuery
Yip: Or remove them all first: If a class name is included as a parameter, then only that class will be removed from the set of matched elements. If no class names are specified in the parameter, all classes will be removed.
What does the function then() mean in JavaScript?
I’ve been seeing code that looks like: Where does then() come from?
What does [object Object] mean?
The default conversion from an object to string is “[object Object]”. As you are dealing with jQuery objects, you might want to do to print the element’s ID. As mentioned in the comments, you should use the tools included in browsers like Firefox or Chrome to introspect objects by doing console.log(whichIsVisible()) instead of alert. Sidenote: … Read more
React.js: Set innerHTML vs dangerouslySetInnerHTML
Yes there is a difference! The immediate effect of using innerHTML versus dangerouslySetInnerHTML is identical — the DOM node will update with the injected HTML. However, behind the scenes when you use dangerouslySetInnerHTML it lets React know that the HTML inside of that component is not something it cares about. Because React uses a virtual … Read more
Uncaught ReferenceError: jQuery is not defined [duplicate]
This question already has answers here: Uncaught ReferenceError: $ is not defined? (40 answers) Closed 5 years ago. I have implemented some JavaScript on my site but I keep getting the following error messages: Uncaught ReferenceError: jQuery is not defined and Uncaught SyntaxError: Unexpected token < This is the JavaScript that I am using in … Read more
How to fix “Cannot read property ‘addEventListener’ of null” error [duplicate]
You are loading the Javascript file in the <head>, before the body of your HTML Is loaded. Therefore your line Has nothing to look up – your button with class guessSubmit doesn’t exist yet. And since guessSubmit is null, it does not contain any properties, hence the error. The easiest solution is to put your … Read more