javascript变量等于iframe

var iframe = document.getElementById('my-iframe');
var iframeWindow = iframe.contentWindow;

var iframe = document.getElementById('my-iframe');
var iframeDocument = iframe.contentDocument || iframe.contentWindow.document;

var iframeIndex = 0; // 根据iframe的索引来选择
var iframeWindow = window.frames[iframeIndex];

var parentWindow = window.parent;
var variableInParentWindow = parentWindow.myVariable;

var topWindow = window.top;
var variableInTopWindow = topWindow.myVariable;