Preview Image Before Upload using jQuery

Show preview image before upload using jquery; In this tutorial, you will learn how to use jQuery to preview an image before it is uploaded with HTML, CSS, and jQuery code.

In modern web development, it’s common to allow users to upload images to your website or application. However, before submitting the image, it’s a good idea to allow the user to preview it, to ensure that they are uploading the correct file. This is where jQuery comes in, allowing you to easily preview the image before it is uploaded.

How to Show Preview Image Before Upload using jQuery

By following the steps outlined in this article, you can easily show image preview using jQuery:

• Step 1: Create HTML Markup
• Step 2: Implement CSS Styling
• Step 3: Implement jQuery Code to Show Preview of Image

Step 1: Create HTML Markup

First, you need to create the HTML markup for our image upload form. You will add an input field of type “file”, and an empty image tag for displaying the preview of the uploaded image. The HTML markup should look something like this:

<form>
  <input type="file" id="image" name="image" accept="image/*">
  <img id="image-preview" src="" alt="Preview Image">
</form>

Here, the “accept” attribute of the input field limits the file type to only image files. you also add an “id” attribute to the input field and the image tag, so that you can reference them in our jQuery code.

Step 2: Implement CSS Styling

Next, you need to add some CSS styling to our HTML markup to ensure that the preview image is displayed correctly. You will set the width and height of the image tag to 200 pixels, and add some padding and margin to make it look good. The CSS styling should look something like this:

#image-preview {
  width: 200px;
  height: 200px;
  padding: 10px;
  margin-top: 10px;
  border: 1px solid #ccc;
  border-radius: 5px;
}

Step 3: Implement jQuery Code to Show Preview of Image

Finally, you need to write some jQuery code to handle the image preview functionality. you will add an event listener to the input field, which will trigger whenever a new file is selected. The code will then create a new FileReader object, which will allow us to read the contents of the selected image file. you will then set the source attribute of the image tag to the contents of the image file, which will display the preview image. The jQuery code should look something like this:

$(function() {
  // Listen for file selection
  $('#image').change(function() {
    // Create a new FileReader object
    var reader = new FileReader();
    // Get the selected file
    var file = this.files[0];
    // Check if the file is an image
    if (file.type.indexOf('image') != -1) {
      // Set the image source to the file contents
      reader.readAsDataURL(file);
      reader.onload = function() {
        $('#image-preview').attr('src', reader.result);
      }
    }
  });
});

t sets up an event listener on an input field with an ID of “image” to listen for file selection. When a file is selected, it creates a new FileReader object to read the contents of the file.

It then gets the selected file by accessing the “files” property of the input field, which contains an array of all selected files. In this example, we are only interested in the first file, so we access it using index 0.

Next, the code checks if the selected file is an image by checking if the “type” property of the file contains the word “image”. If the file is indeed an image, it reads the contents of the file using the “readAsDataURL” method of the FileReader object.

Finally, the code sets the source attribute of an image tag with an ID of “image-preview” to the contents of the selected file. This displays the preview image on the webpage.

Overall, this code demonstrates a simple and effective way to preview an image before it is uploaded using jQuery. It’s important to note that this code only handles client-side validation and that server-side validation should also be implemented to ensure the security and integrity of the uploaded files.

Conclusion

Previewing an image before it is uploaded is a useful feature for improving the user experience of your website or application. With jQuery, it’s easy to implement this functionality, by adding an event listener to the input field, and creating a new FileReader object to read the contents of the selected file.

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