Test-Driven JavaScript Development

has.js

has.js tests are very simple to perform and use has('feature') like syntax and return a Boolean value. The code in the previous example could be written as:

<script>
    var videoElement = "";
    $(document).ready(function(){
    if(has("video")){
        //  video is supported by the browser and can play it.
        $("#result").html("Video is supported");
        videoElement = document.createElement('video');
        $("body").append(videoElement);
    }else{
        // load via flash or something else
        $("#result").html("Video is not supported, use Flash or something else.");
    }
});
</script>

In this case, has("video") will return a Boolean value to help developer make a decision. Sometimes features are partially supported. To understand this, let's take the same example of displaying video ...