详解JavaScript跨域总结与解决办法

document.domain = 'a.';
var ifr = document.createElement('iframe');
ifr.src = 'http://script.a./b.html';
ifr.style.display = 'none';
document.body.appendChild(ifr);
ifr.onload = function(){
  var doc = ifr.contentDocument || ifr.contentWindow.document;
  // 在这里操纵b.html
  alert(doc.getElementsByTagName("h1")[0].childNodes[0].nodeValue);
};

document.domain = 'a.';

js.onload = js.onreadystatechange = function() {
  if (!this.readyState || this.readyState === 'loaded' || this.readyState === 'plete') {
    // callback在此处执行
    js.onload = js.onreadystatechange = null;
  }
};

function startRequest(){
  var ifr = document.createElement('iframe');
  ifr.style.display = 'none';
  ifr.src = 'http://.blogs./lab/cscript/cs2.html#paramdo';
  document.body.appendChild(ifr);
}

function checkHash() {
  try {
    var data = location.hash ? location.hash.substring(1) : '';
    if (console.log) {
      console.log('Now the data is '+data);
    }
  } catch(e) {};
}
setInterval(checkHash, 2000);

//模拟一个简单的参数处理操作
switch(location.hash){
  case '#paramdo':
    callBack();
    break;
  case '#paramset':
    //do something……
    break;
}

function callBack(){
  try {
    parent.location.hash = 'somedata';
  } catch (e) {
    // ie、chrome的安全机制无法修改parent.location.hash，
    // 所以要利用一个中间的blogs域下的代理iframe
    var ifrproxy = document.createElement('iframe');
    ifrproxy.style.display = 'none';
    ifrproxy.src = 'http://a./test/cscript/cs3.html#somedata';  // 注意该文件在"a."域下
    document.body.appendChild(ifrproxy);
  }
}

//因为parent.parent和自身属于同一个域，所以可以改变其location.hash的值
parent.parent.location.hash = self.location.hash.substring(1);

<script type="text/javascript">
  window.name = 'I was there!';  // 这里是要传输的数据，大小一般为2M，IE和firefox下可以大至32M左右
                   // 数据格式可以自定义，如json、字符串
</script>

<script type="text/javascript">
  var state = 0, 
  iframe = document.createElement('iframe'),
  loadfn = function() {
    if (state === 1) {
      var data = iframe.contentWindow.name;  // 读取数据
      alert(data);  //弹出'I was there!'
    } else if (state === 0) {
      state = 1;
      iframe.contentWindow.location = "http://a./proxy.html";  // 设置的代理文件
    } 
  };
  iframe.src = 'http://b./data.html';
  if (iframe.attachEvent) {
    iframe.attachEvent('onload', loadfn);
  } else {
    iframe.onload = loadfn;
  }
  document.body.appendChild(iframe);
</script>

<script type="text/javascript">
  iframe.contentWindow.document.write('');
  iframe.contentWindow.close();
  document.body.removeChild(iframe);
</script>

<iframe id="ifr" src="b./index.html"></iframe>
<script type="text/javascript">
window.onload = function() {
  var ifr = document.getElementById('ifr');
  var targetOrigin = 'http://b.'; // 若写成'http://b./c/proxy.html'效果一样
                    // 若写成'http://c.'就不会执行postMessage了
  ifr.contentWindow.postMessage('I was there!', targetOrigin);
};
</script>

<script type="text/javascript">
  window.addEventListener('message', function(event){
    // 通过origin属性判断消息来源地址
    if (event.origin == 'http://a.') {
      alert(event.data);  // 弹出"I was there!"
      alert(event.source); // 对a.、index.html中window对象的引用
                 // 但由于同源策略，这里event.source不可以访问window对象
    }
  }, false);