Basic Blob Fallback Support

blob.support.js

var __support = {
    // Blob
    Blob: !!window.Blob,
    BlobSlice: !!Blob.prototype.slice,
    URL: !!window.URL,
}
var prefixes = ['webkit', 'Webkit', 'WebKit', 'moz', 'Moz', 'o', 'O', 'ms', 'Ms', 'MS', 'khtml', 'Khtml', ''];

// Number of prefixes
var i = prefixes.length;

// Prefix window.URL
if(!__support.URL) {
    // Fallback for BlobBuilder
    while ((i -= 1) > -1) {
        window.URL = window.URL || window[prefixes[i] + 'URL'];
    }
}

// Prefix Blob.slice
if(!__support.BlobSlice) {
    // Fallback for BlobBuilder
    while ((i -= 1) > -1) {
        Blob.prototype.slice = Blob.prototype.slice || Blob.prototype[prefixes[i] + 'Slice'];
    }
}

// Simple BlobBuilder fallback for basic Blob usage
if(!__support.Blob) {

    // Prefixes for BlobBuilder
    while ((i -= 1) > -1) {
        window.BlobBuilder = window.BlobBuilder || window[prefixes[i] + 'BlobBuilder'];
    }

    // BlobBuilder fallback for Blob
    window.Blob = function(data, obj) {
        var n;

        var builder = new BlobBuilder;

        // Append the data
        for (n in data) {
            builder.append(data[n]);
        }

        // Return the blob
        return builder.getBlob((obj && obj.type) ? obj.type : undefined);
    }
}