Category: JavaScript Answers

Sometimes, we want to name a JavaScript function and execute it immediately.

In this article, we’ll look at how to name a JavaScript function and execute it immediately.

How to name a JavaScript function and execute it immediately?

To name a JavaScript function and execute it immediately, we can use an IIFE.

For instance, we write

(function addEventsAndStuff() {
  //...
})();

to define the addEventsAndStuff function and then call it immediately by wrapping it in parentheses.

And then we call it with ().

Conclusion

To name a JavaScript function and execute it immediately, we can use an IIFE.

Sometimes, we want to detect iPad or iPhone web view via JavaScript.

In this article, we’ll look at how to detect iPad or iPhone web view via JavaScript.

How to detect iPad or iPhone web view via JavaScript?

To detect iPad or iPhone web view via JavaScript, we check window.navigator.userAgent and window.navigator.standalone.

For instance, we write

const standalone = window.navigator.standalone;
const userAgent = window.navigator.userAgent.toLowerCase();
const safari = /safari/.test(userAgent);
const ios = /iphone|ipod|ipad/.test(userAgent);

if (ios) {
  if (!standalone && safari) {
    //browser
  } else if (standalone && !safari) {
    //standalone
  } else if (!standalone && !safari) {
    //uiwebview
  }
} else {
  //not iOS
}

to get the user agent with window.navigator.userAgent

And window.navigator.standalone being false means that the page is opened in a web view in an app.

Then we check if the user agent is safari and ios with test.

We then check if the page is opened in ios. If it is then ios is true.

And then in the inner if block, we check for combinations of standalone and safari to see if it’s opened in a Safari web view.

If the page is opened in a web view, then !standalone && !safari is true.

Conclusion

To detect iPad or iPhone web view via JavaScript, we check window.navigator.userAgent and window.navigator.standalone.

Sometimes, we want to change SVG image color with JavaScript.

In this article, we’ll look at how to change SVG image color with JavaScript.

How to change SVG image color with JavaScript?

To change SVG image color with JavaScript, we can set the fill attribute value.

For instance, we add an svg with

<svg id="svg" fill="AliceBlue">
  <circle r="50" cx="70" cy="70" />
</svg>

Then we write

const svgElement = document.getElementById("svg");
svgElement.style.fill = "green";

to select the svg element with getElementById.

Then we set the fill attribute’s value by setting svgElement.style.fill to the color we want.

Conclusion

To change SVG image color with JavaScript, we can set the fill attribute value.

Sometimes, we want to get how many times a character occurs in a string with JavaScript.

In this article, we’ll look at how to get how many times a character occurs in a string with JavaScript.

How to get how many times a character occurs in a string with JavaScript?

To get how many times a character occurs in a string with JavaScript, we can use the string match method.

For instance, we write

const string = "aajlkjjskdjfAlsjfghgfjjgfkk";
console.log(string.match(/a/gi).length)

to call string.match with a regex that matches all instances of 'a' in a case insensitive manner.

match returns an array of matches, so we can use the length property to get the count of the matches.

Conclusion

To get how many times a character occurs in a string with JavaScript, we can use the string match method.

Sometimes, we want to programmatically trigger an input event with JavaScript.

In this article, we’ll look at how to programmatically trigger an input event with JavaScript.

How to programmatically trigger an input event with JavaScript?

To programmatically trigger an input event with JavaScript, we call the dispatchEvent method.

For instance, we write

const event = new Event("input", {
  bubbles: true,
  cancelable: true,
});

element.dispatchEvent(event);

to create a new input event object with the Event object.

We call Event with an object to set the options for the object.

Then we call element.dispatchEvent with event to trigger the event programmatically.

Conclusion

To programmatically trigger an input event with JavaScript, we call the dispatchEvent method.