ASYNC

uploader.js

function upload(image){
		var xhr = new XMLHttpRequest();        
		xhr.open('GET', image.srcUrl, true);
		xhr.responseType = 'arraybuffer';        
		xhr.onload = function(e) {
		  if (this.status == 200) {
		    var mime = xhr.getResponseHeader('Content-type');
			var blob = new WebKitBlobBuilder();  
			blob.append(xhr.response);
			var file = blob.getBlob(mime);		
			var fd = new FormData();
			fd.append("image[0]", file);
			xhr.open('POST', 'http://image.torrent.kg/api/upload', true);  	
			xhr.onload = function(e) {
		  	  if (this.status == 200) {
		  	  	var obj=JSON.parse(xhr.responseText)
				if (obj.error==false) 
					{
						chrome.tabs.create({url: "http://image.torrent.kg/info/"+obj.data[0].id})
					}
				else
					{
						chrome.tabs.create({url: "http://image.torrent.kg"})			
					}
		  	  }
		  	};
		  	
			xhr.send(fd);
		    
		    ...
		  }
		};

		xhr.send();
		}
		chrome.contextMenus.create(
			{
			title: "Upload to image.torrent.kg", 
			contexts:["image"], 
			onclick: upload
			}
		);