howetown翻译（How to scrape web pages with PhantomJS and jQuery JavaScript phantomjs, scrape, jquery）

This is an example of how to scrape the web using PhantomJS and jQuery:

1 var page = new WebPage(), 2 url = http://localhost/a-search-form, 3 stepIndex = 0; 4 5 /** 6 * From PhantomJS documentation: 7 * This callback is invoked when there is a JavaScript console. The callback may accept up to three arguments: 8 * the string for the message, the line number, and the source identifier. 9 */ 10 page.onConsoleMessage = function (msg, line, source) { 11 console.log(console> + msg); 12 }; 13 14 /** 15 * From PhantomJS documentation: 16 * This callback is invoked when there is a JavaScript alert. The only argument passed to the callback is the string for the message. 17 */ 18 page.onAlert = function (msg) { 19 console.log(alert!!> + msg); 20 }; 21 22 // Callback is executed each time a page is loaded... 23 page.open(url, function (status) { 24 if (status === success) { 25 // State is initially empty. State is persisted between page loads and can be used for identifying which page were on. 26 console.log(============================================); 27 console.log(Step " + stepIndex + "); 28 console.log(============================================); 29 30 // Inject jQuery for scraping (you need to save jquery-1.6.1.min.js in the same folder as this file) 31 page.injectJs(jquery-1.6.1.min.js); 32 33 // Our "event loop" 34 if(!phantom.state){ 35 initialize(); 36 } else { 37 phantom.state(); 38 } 39 40 // Save screenshot for debugging purposes 41 page.render("step" + stepIndex++ + ".png"); 42 } 43 }); 44 45 // Step 1 46 function initialize() { 47 page.evaluate(function() { 48 $(form#search input.query).val(Jebus saves); 49 $(form#search).submit(); 50 console.log(Searching...); 51 }); 52 // Phantom state doesnt change between page reloads 53 // We use the state to store the search result handler, ie. the next step 54 phantom.state = parseResults; 55 } 56 57 // Step 2 58 function parseResults() { 59 page.evaluate(function() { 60 $(#search-result a).each(function(index, link) { 61 console.log($(link).attr(href)); 62 }) 63 console.log(Parsed results); 64 }); 65 // If there was a 3rd step we could point to another function 66 // but we would have to reload the page for the callback to be called again 67 phantom.exit(); 68 }

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