Category: JavaScript

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JavaScript Answers

How to Use the window.open Method to Open a mailto URL with JavaScript?

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Sometimes, we want to use the window.open method to open a mailto URL with JavaScript.

In this article, we’ll look at how to use the window.open method to open a mailto URL with JavaScript.

Use the window.open Method to Open a mailto URL with JavaScript

To use the window.open method to open a mailto URL, we can call window.open with '_self' as the 2nd argument.

For instance, we write:

const emailTo = 'example@example.com'
const emailCC = 'cc@example.com'
const emailSub = 'subject'
const emailBody = 'body'
window.open(`mailto:${emailTo}?cc=${emailCC}&subject=${emailSub}&body=${emailBody}`, '_self');

We set the emailTo, emailCC, emailSub and emailBody variables to the values we want.

emailTo is the email address to mail to.

emailCC is the email address to CC.

emailSub is the subject of the email.

emailBody is the email body.

We call window.open with ‘mailto:${emailTo}?cc=${emailCC}&subject=${emailSub}&body=${emailBody}‘ as the first argument to open that URL.

The 2nd argument is '_self' so it won’t open a new tab.

Now when we run the code, we should see the default email client open up with the receiver’s address, CC address, subject and body filled in.

Conclusion

To use the window.open method to open a mailto URL, we can call window.open with '_self' as the 2nd argument.

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JavaScript Answers

How to Change Font Size with JavaScript?

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Sometimes, we want to change font size with JavaScript.

In this article, we’ll look at how to change font size with JavaScript.

Change Font Size with JavaScript

To change font size with JavaScript, we can set the style.fontSize property of the element.

For instance, if we have the following HTML:

<span>hello</span>

Then we write the following JavaScript code:

const span = document.querySelector("span");
span.style.fontSize = "25px";

to select the span element and set the font size of its content.

We select the element with document.querySelector and assign the returned element to span.

Then we set span.style.fontSize to '25px' to set the font size of its content to 25px.

Now we should see larger text displayed.

Conclusion

To change font size with JavaScript, we can set the style.fontSize property of the element.

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JavaScript Answers

How to Change Image Opacity Using JavaScript?

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Sometimes, we want to change image opacity using JavaScript.

In this article, we’ll look at how to change image opacity using JavaScript.

Change Image Opacity Using JavaScript

To change image opacity using JavaScript, we can use the setAttribute method.

For instance, if we have the following image:

<img src='https://picsum.photos/200'>

We write:

document
  .querySelector("img")
  .setAttribute("style", "opacity:0.5; -moz-opacity:0.5; filter:alpha(opacity=50)");

to select the img element with document.querySelector("img").

Then we call setAttribute with 'style' and "opacity:0.5; -moz-opacity:0.5; filter:alpha(opacity=50)" to set the style attribute of the img element to opacity:0.5; -moz-opacity:0.5; filter:alpha(opacity=50).

Therefore, we see that the resulting image displayed is translucent.

Conclusion

To change image opacity using JavaScript, we can use the setAttribute method.

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JavaScript Answers jQuery

How to Set Margin CSS Properties with JavaScript?

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Sometimes, we want to set margin CSS properties with JavaScript.

In this article, we’ll look at how to set margin CSS properties with JavaScript.

Set Margin CSS Properties with JavaScript

To set margin CSS properties with JavaScript, we can call the css method to change the margin CSS properties.

For instance, if we have the following HTML:

<div>
  hello
</div>

Then we write:

$('div').css('margin-left', '100px');

to select the div with $('div').

Then we call the css method on the returned div jQuery object with the property key and value we want to set respectively.

Therefore, we set margin-left to 100px.

The unit must be included.

Now we should see a 100px left margin added to the div.

Conclusion

To set margin CSS properties with JavaScript, we can call the css method to change the margin CSS properties.

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React Answers

How to fix Excel file download being corrupted in React and Axios?

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To fix Excel file download being corrupted in React and Axios, we set the responseType option when we make our Axios request to 'arrayBuffer'.

For instance, we write

import React, { Component } from "react";
import { saveAs } from "file-saver";

//...

const C = () => {
  const exportIssues = async () => {
    const response = await axios.get("/issues/export", {
      responseType: "arraybuffer",
    });

    const blob = new Blob([response.data], {
      type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    });
    saveAs(blob, "file.xlsx");
  };

  //...
};

to create the exportIssues function that calls axios.get with the URL for the Excel file.

We set the responseType to 'arraybuffer' to download the file as a binary file.

And then we transform the response.data response data to a Blob with the Blob constructor.

And then we call saveAs with the returned blob and the file name for the file.