iframe子页面调用父页面js函数

window.parent.document.getElementById("test").value; 

jQuery方法为： 

$(window.parent.document).contents().find("test").val(); 

例:

父:

<div id="page-wrapper" class="gray-bg dashbard-1">
    <div class="row J_mainContent" id="content-main" class="tab-content">
        <iframe id="J_iframe" width="100%" height="100%" src="index_v1.html" frameborder="0" data-id="index_v1.html" seamless></iframe>
    </div>
</div>

子方法:

$('.btn-skip').click(function(){
    var url = 'index_v5.html';
    $(window.parent.document).contents().find("#J_iframe").attr('src', url);
});