Category: JavaScript Answers

Sometimes, we want to display a JavaScript variable in HTML body.

In this article, we’ll look at how to display a JavaScript variable in HTML body.

How to display a JavaScript variable in HTML body?

To display a JavaScript variable in HTML body, we set the innerHTML property of the element.

For instance, we write

<h1>"The value for number is: " <span id="myText"></span></h1>

to add some elements.

Then we write

const number = "123";
document.getElementById("myText").innerHTML = number;

to select the span with getElementById and then set its innerHTML property to number to render number in the span.

Conclusion

To display a JavaScript variable in HTML body, we set the innerHTML property of the element.

Sometimes, we want to fire a change event on a HTML select element if the new value is the same as the old with JavaScript.

In this article, we’ll look at how to fire a change event on a HTML select element if the new value is the same as the old with JavaScript.

How to fire a change event on a HTML select element if the new value is the same as the old with JavaScript?

To fire a change event on a HTML select element if the new value is the same as the old with JavaScript, we add an empty option.

For instance, we write

<select onchange="jsFunction()">
  <option></option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
</select>

to add an empty option element so that jsFunction is called whether the selected value is the same as the old one or not.

Conclusion

To fire a change event on a HTML select element if the new value is the same as the old with JavaScript, we add an empty option.

Sometimes, we want to iterate over values of object with JavaScript.

In this article, we’ll look at how to iterate over values of object with JavaScript.

How to iterate over values of object with JavaScript?

To iterate over values of object with JavaScript, we use the Object.entries method.

For instance, we write

const map = { key1: "value1", key2: "value2" };

for (const [key, value] of Object.entries(map)) {
  console.log(`${key}: ${value}`);
}

to use a for-of loop to loop through the array entries returned by Object.entries.

Object.entries returns an array of array of key-value pair strings.

We get the key with key and value from value.

Conclusion

To iterate over values of object with JavaScript, we use the Object.entries method.

Sometimes, we want to close an iframe within iframe itself with JavaScript.

In this article, we’ll look at how to close an iframe within iframe itself with JavaScript.

How to close an iframe within iframe itself with JavaScript?

To close an iframe within iframe itself with JavaScript, we use the remove the iframe.

For instance, we get the parent of the iframe and then call closeFrame on it by writing

parent.closeIFrame();

where closeIFrame is

function closeIFrame() {
  document.getElementById("youriframeid").remove();
}

in the parent.

We select the iframe with getElementById.

And then we call remove to remove it.

Conclusion

To close an iframe within iframe itself with JavaScript, we use the remove the iframe.

Sometimes, we want to configure dynamic routes with Express.js and JavaScript.

In this article, we’ll look at how to configure dynamic routes with Express.js and JavaScript.

How to configure dynamic routes with Express.js and JavaScript?

To configure dynamic routes with Express.js and JavaScript, we can make a route accept URL parameters.

For instance, we write

app.get("/article/:id", (req, res) => {
  res.render("article" + req.params.id);
});

to add the /article/:id route.

:id is the placeholder for the id route parameter.

And we get the value of that from req.params.id.

Conclusion

To configure dynamic routes with Express.js and JavaScript, we can make a route accept URL parameters.