Check if a link is an image

Question

I need to check whether a URL is an image.

The answer here

/(jpg|gif|png)$/.test(...

raises a false positive in my (special) case when there's an extension in a non-image URL

http://www.example.com/jpg/bpgpage/

(PS: can't use jquery, only javascript/regex)

Answer 1

Maybe you can add a dot . before the regular expression, as such:

  /\.(jpg|gif|png)$/.test( ..

That will try to match .jpg, .gif and .png in URLs.
The regular expression you mentioned though, does try to search for jpg, gif and png only at the end of the URL, so I'm not sure how it matched http://www.example.com/jpg/bpgpage/.

If you ommit the dot . though, it will still match http://www.example.com/jpg

Answer 2

Provided that the uri ends with the extension, this should work every time.

Code:

var isUriImage = function(uri) {
    //make sure we remove any nasty GET params 
    uri = uri.split('?')[0];
    //moving on, split the uri into parts that had dots before them
    var parts = uri.split('.');
    //get the last part ( should be the extension )
    var extension = parts[parts.length-1];
    //define some image types to test against
    var imageTypes = ['jpg','jpeg','tiff','png','gif','bmp'];
    //check if the extension matches anything in the list.
    if(imageTypes.indexOf(extension) !== -1) {
        return true;   
    }
}

Example:

• http://jsfiddle.net/fMCFB/1/