function fetch(url, cb, type) {
	if (url.indexOf('//') === 0) {
		url = 'http:'+url
	}
	let x = new XMLHttpRequest()
	x.open('get', url, true)
	if (type) {
		x.responseType = type
	}
	x.onload = function () {
		console.log(x.getResponseHeader('content-type'))
		cb(URL.createObjectURL(x.response), x.getResponseHeader('content-type'))
	}
	x.onerror = function () {
		console.error('error')
		cb(null)
	}
	x.send()
}

chrome.extension.onMessage.addListener(function(request, sender, sendResponse) {
	fetch(request, sendResponse, 'blob')
	return true
})