hack在微信等webview中无法修改title的情况

页面 
    document.title = 'test'; 
    var iframe = document.createElement('iframe');
    iframe.style.visibility = 'hidden'; 
    iframe.style.width = '1px'; 
    iframe.style.height = '1px'; 
    iframe.onload = function () { 
        setTimeout(function () {
            document.body.removeChild(iframe); 
        },0); 
    }; 
    document.body.appendChild(iframe);
},0);