如何从存储网页代码的变量中提取指定<span>元素的值？

Hey there! I've got you covered on pulling that dynamic Bitcoin price value. Let's break down how to make this work with your existing jQuery code:

Step-by-Step Implementation #

The data.contents returned from your API call is the full HTML of the CoinMarketCap page. We can convert this raw HTML into a jQuery object, then use targeted selectors to grab the exact element you need.

Here's the complete updated code snippet:

$.getJSON('http://www.whateverorigin.org/get?url=' + encodeURIComponent('https://coinmarketcap.com/currencies/bitcoin/') + '&callback=?', function(data) {
  // Turn the raw HTML string into a manipulable jQuery DOM object
  const $pageContent = $(data.contents);
  
  // Target the specific span using combined class + attribute selector
  const targetPriceElement = $pageContent.find('span.text-large2[data-currency-value]');
  
  // Extract the price text, trimming any extra whitespace
  const bitcoinPriceText = targetPriceElement.text().trim();
  
  // Optional: Convert text to a numeric value if you need to run calculations
  const bitcoinPriceNumber = parseFloat(bitcoinPriceText);
  
  // Use the price however you need!
  console.log('Current Bitcoin Price:', bitcoinPriceText);
  console.log('Price as Numeric Value:', bitcoinPriceNumber);
});

Key Details to Keep in Mind #

• Selector Accuracy: Using span.text-large2[data-currency-value] ensures we only match spans that have both the correct class and the data-currency-value attribute, avoiding accidental matches with other elements on the page.
• Whitespace Cleanup: The .trim() method removes any leading/trailing spaces that might be hidden in the element's text content.
• Page Structure Changes: Heads up—if CoinMarketCap ever updates their page markup (like changing class names or attributes), you'll need to adjust the selector to match the new structure.

内容的提问来源于stack exchange，提问作者marsnebulasoup