Permission denied to access property 'document'?

function OpenParentTab(parentPageId){
$(window.parent.document).find("#currentTabSelectedIds").val(getSelections());//这行报错
$(window.parent.document).find("#"+parentPageId).click();
}父页面有个<iframe src="XXX.jsp">,上面这段代码是子页面(XXX.jsp)里的,getSelections()方法获取选中的ID,可以忽视.
currentTabSelectedIds是父页面一个<input type="currentTabSelectedIds">,iframe不能给包含页面(父页面)的元素赋值标题的错误是Firefox打印的,IE9的调试工具也是这里不能访问