PhantomJS viewportSize属性

var wpage = require('webpage').create(); 
wpage.viewportSize;

var wpage = require('webpage').create(); 
wpage.open('http://localhost/tasks/page1.html', function (status) {  
   console.log(JSON.stringify(wpage.viewportSize));
   wpage.viewportSize = { 
      'width' : 800, 
      'height' : 800 
   } 
   console.log(JSON.stringify(wpage.viewportSize));
   phantom.exit(); 
});

{"height":300,"width":400} 
{"height":800,"width":800}