为什么普通的JavaScript在CasperJS中不起作用？ [英] Why doesn't plain JavaScript work in CasperJS?

问题描述

我是CasperJS的新手。 this.echo（this.getTitle（））; 如何工作，但 console.log（ Page Title，document.title）; 不是吗？另外，为什么我的document.querySelector无法正常工作？有人有很好的解释吗？我在CasperJS文档中的哪里找到答案？

I'm new to CasperJS. How come this.echo(this.getTitle()); works but console.log("Page Title ", document.title); doesn't? Also why isn't my document.querySelector working? Does anyone have a good explanation? Where in the CasperJS documentation can I find the answer?

这是我的代码：

var casper = require('casper').create();
var url = 'http://www.example.com/';

 casper.start(url, function() {
     this.echo(this.getTitle()); // works
     this.echo(this.getCurrentUrl()); // works
});

casper.then(function(){
    this.echo(this.getCurrentUrl()); // works
    console.log("this is URL: ", document.URL); // doesn't work
    console.log("Page Title ", document.title); // doesn't work
    var paragraph = document.querySelectorAll('p')[0].innerHTML;
    console.log(paragraph); // doesn't work
});

casper.run();

编辑：
我正在使用casper.then casper.evaluate现在，它仍然无法正常工作。有什么想法吗？

I'm using casper.thenEvaluate and casper.evaluate now and it's still not working. Any ideas?

var casper = require('casper').create();
var url = 'http://www.example.com/';

casper.start(url, function() {
    this.echo(this.getTitle()); // works
    this.echo(this.getCurrentUrl()); // works
    console.log('page loaded: '); // works
});

casper.thenEvaluate(function(){
    var paragraph = document.querySelectorAll('p')[0].innerHTML; // doesn't work
    console.log(paragraph); // doesn't work
    console.log("Page Title ", document.title); // doesn't work
});

casper.run();

推荐答案

您必须调用依赖于<$ c的函数$ c>文档和 this.evaluate ：

var paragraph = this.evaluate(function() {
    return document.querySelector('p').innerHtml;
});

如有疑问，请咨询文档。

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