How to check whether an image is loaded or not ?
While inserting images in HTML pages sometimes the image may fail to load due to:
- Getting the image URL wrong
- poor internet connection
So we may want to check if the image is not loading due to these reasons. To check we can use the below methods
Method 1:
Using attributes of <img> to check whether an image is loaded or not. The attributes we will use are:
- onload: The onload event is triggered when an image is loaded and is executed
- onerror: The onerror event is triggered if an error occurs during the execution
Example:
html
<!DOCTYPE html><html> <head> <title>Image load check</title> </head> <body> <img src= onload="javascript: alert('The image has been loaded')" onerror="javascript: alert('The image has failed to load')" /> </body></html> |
Output:
when image is successfully loaded
when image loading fails
Method 2:
Using the image complete property in HTML DOM
This property returns a boolean value if the image is loaded it returns true else it returns false
Example:
html
<!DOCTYPE html><html> <head> <title>Checking if image is loaded</title> </head> <script type="text/javascript"> window.addEventListener("load", event => { var image = document.querySelector('img'); var load = image.complete; alert(load);}); </script> <body> <img src= </body></html> |
Here the variable load checks if the image is loaded or not. If an image is loaded then true is alerted else false is alerted.
Output:
when image is successfully loaded
when image load fails
Supported Browsers:
- Google Chrome
- Firefox
- Internet Explorer
- Safari
- Opera
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