Check FileReaderSync Support

JavaScript

// Check FileReaderSync support

var supportsFilereaderSync = false;

(function() {
        
    function generateWorkerUrl(script) {
        var BlobBuilder = window.BlobBuilder || window.WebKitBlobBuilder || window.MozBlobBuilder;
        var URL = window.URL || window.webkitURL;
        var Worker = window.Worker;
        
        if (Worker && BlobBuilder && URL) {
            var bb = new BlobBuilder();
            bb.append(script);
            return URL.createObjectURL(bb.getBlob());
        }
    
        return null;
    }

    var checkSyncSupportURL = generateWorkerUrl(
        "self.addEventListener('message',function(e){ postMessage(!!FileReaderSync); }, false);"     
    );
    
    if (checkSyncSupportURL) {
        var worker = new Worker(checkSyncSupportURL);
        worker.onmessage = function(e) {
            supportsFilereaderSync = e.data;
        };
        worker.postMessage();
    }
})();

//document.write(supportsFilereaderSync);

setTimeout(function() {
    document.write(supportsFilereaderSync);
    alert(supportsFilereaderSync);
}, 100);