Author: John Au-Yeung

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.

Sometimes, we want to determine the OS path separator in JavaScript.

In this article, we’ll look at how to determine the OS path separator in JavaScript.

How to determine the OS path separator in JavaScript?

To determine the OS path separator in JavaScript, we can use the path module.

For instance, we write

const path = require("path");
console.log(path.sep);

to use the path.sep property to return the path separator string for the OS that the Node app is running on.

Conclusion

To determine the OS path separator in JavaScript, we can use the path module.