XHR.js

/*
 * Copyright (C) 2013 Nikita Krupenko
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

function sendXHR(method, url, callback, data, contentType) {
    if (!method || !url) {
        return null
    }

    var request = new XMLHttpRequest()
    var requestUrl = (method === 'GET' ? '%1%2'.arg(url).arg(data ? "?%1".arg(data) : "") : url)
    request.open(method, requestUrl)
    request.onreadystatechange = function() {
        if (request.readyState === XMLHttpRequest.DONE) {
            if (callback) {
                callback(request)
            }
        }
    }
    if (method !== 'GET') {
        request.setRequestHeader('Content-Type', contentType ? contentType
                                                             : 'application/x-www-form-urlencoded')
        request.setRequestHeader('Content-Length', data ? data.length : 0)
        request.send(data)
    } else {
        request.send()
    }

    return request
}