当您使用BeautifulSoup 时，您需要了解当您给它一个html 文档时它可以给出什么输出。这是您在问题中使用代码获得的整个文档，即变量 token 中存在的内容。
<!DOCTYPE html>
<!--[if lt IE 7]> <html class="no-js ie6 oldie" lang="en-US"> <![endif]-->
<!--[if IE 7]> <html class="no-js ie7 oldie" lang="en-US"> <![endif]-->
<!--[if IE 8]> <html class="no-js ie8 oldie" lang="en-US"> <![endif]-->
<!--[if gt IE 8]><!-->
<html class="no-js" lang="en-US">
<!--<![endif]-->
<head>
<title>
Access denied | poocoin.app used Cloudflare to restrict access
</title>
<meta charset="utf-8"/>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type"/>
<meta content="IE=Edge,chrome=1" http-equiv="X-UA-Compatible"/>
<meta content="noindex, nofollow" name="robots"/>
<meta content="width=device-width,initial-scale=1" name="viewport"/>
<link href="/cdn-cgi/styles/main.css" id="cf_styles-css" media="screen,projection" rel="stylesheet" type="text/css"/>
<script async="" src="/cdn-cgi/bm/cv/669835187/api.js">
</script>
</head>
<body>
<div id="cf-wrapper">
<div class="cf-alert cf-alert-error cf-cookie-error hidden" data-translate="enable_cookies" id="cookie-alert">
Please enable cookies.
</div>
<div class="p-0" id="cf-error-details">
<header class="mx-auto pt-10 lg:pt-6 lg:px-8 w-240 lg:w-full mb-15 antialiased">
<h1 class="inline-block md:block mr-2 md:mb-2 font-light text-60 md:text-3xl text-black-dark leading-tight">
<span data-translate="error">
Error
</span>
<span>
1020
</span>
</h1>
<span class="inline-block md:block heading-ray-id font-mono text-15 lg:text-sm lg:leading-relaxed">
Ray ID: 67c75596dc9cdca5 •
</span>
<span class="inline-block md:block heading-ray-id font-mono text-15 lg:text-sm lg:leading-relaxed">
2021-08-10 06:58:11 UTC
</span>
<h2 class="text-gray-600 leading-1.3 text-3xl lg:text-2xl font-light">
Access denied
</h2>
</header>
<section class="w-240 lg:w-full mx-auto mb-8 lg:px-8">
<div class="w-1/2 md:w-full" id="what-happened-section">
<h2 class="text-3xl leading-tight font-normal mb-4 text-black-dark antialiased" data-translate="what_happened">
What happened?
</h2>
<p>
This website is using a security service to protect itself from online attacks.
</p>
</div>
</section>
<div class="cf-error-footer cf-wrapper w-240 lg:w-full py-10 sm:py-4 sm:px-8 mx-auto text-center sm:text-left border-solid border-0 border-t border-gray-300">
<p class="text-13">
<span class="cf-footer-item sm:block sm:mb-1">
Cloudflare Ray ID:
<strong class="font-semibold">
67c75596dc9cdca5
</strong>
</span>
<span class="cf-footer-separator sm:hidden">
•
</span>
<span class="cf-footer-item sm:block sm:mb-1">
<span>
Your IP
</span>
: 103.162.8.200
</span>
<span class="cf-footer-separator sm:hidden">
•
</span>
<span class="cf-footer-item sm:block sm:mb-1">
<span>
Performance & security by
</span>
<a href="https://www.cloudflare.com/5xx-error-landing" id="brand_link" rel="noopener noreferrer" target="_blank">
Cloudflare
</a>
</span>
</p>
</div>
<!-- /.error-footer -->
</div>
<!-- /#cf-error-details -->
</div>
<!-- /#cf-wrapper -->
<script type="text/javascript">
window._cf_translation = {};
</script>
<script type="text/javascript">
(function(){window['__CF$cv$params']={r:'67c75596dc9cdca5',m:'7d5cb070f52bc2658c47cfc88a34832f4146bc1d-1628578691-1800-AR1RssYylCV1f2kIgs0CPVdq4ZoKz1sRl9UYE21Ha1aj3nICL+7XnFzztlixt0HmssNjZllMWXNfOzKg8lz3ARfY0damLC5V/icRyggdI3F8p8ff60JVxyOhbPddj1CHEN1tln1DXTGeD22FuS1QMeDRr71Zt702lXjmpb5+pIM7TRuE62iKa+JcTuP0oC3ajFUxmStjY0GhQ+8F1LcKVXuP54xCzOzN5t8t87Bx7KDyu6Bn9pOew7YNYJRrDxaFUW7UqbF3XNw6yb5HqE+LCikS1PxIUKa3s3SRSgsFiyzz884GhqB2dHZo474r19GcyY1JYGe2BohY8p4/oPnGO/mgGKJ6tlbBkuluL0lohBVDtbLAUo0atxlDUxIgooWbVZshvx8x0F99vHzlB0AriSihU/oGlATjttPFIcr+6gvk',s:[0x3f2b1d591e,0x8f03d56274],}})();
</script>
<script data-cf-beacon='{"rayId":"67c75596dc9cdca5","token":"b7a3c0b8fa4646c3a017dc0af118d444","version":"2021.7.0","si":10}' defer="" src="https://static.cloudflareinsights.com/beacon.min.js">
</script>
</body>
</html>
上面的整个文档中只有一个a 标签，如下所示：
<a href="https://www.cloudflare.com/5xx-error-landing" id="brand_link" rel="noopener noreferrer" target="_blank">
Cloudflare
</a>
从而使您的输出None。您必须使用Selenium 或Scrapy 在这里获得您想要的输出，或者您可以提供一个输入，使BeautifulSoup 提供您想要的输出。
单独使用Selenium：
from webdriver_manager.chrome import ChromeDriverManager
from selenium import webdriver
option = webdriver.ChromeOptions()
# option.add_argument('--headless')
option.add_argument("--log-level=3")
option.add_experimental_option('excludeSwitches', ['enable-logging'])
CDM = ChromeDriverManager(log_level='0')
driver = webdriver.Chrome(CDM.install(), options=option)
tokenurl = "https://poocoin.app/tokens/0xb393d44b9aaecf946925c0198b71f2a5163ce78b"
driver.get(tokenurl)
time.sleep(2)
a = driver.find_element_by_class_name('text-danger.bg-dark.rounded.p-2.mt-1.d-inline-block.text-decoration-underline').text
print(a)
driver.quit()
通过Selenium 向BS 提供更好的输入：
from webdriver_manager.chrome import ChromeDriverManager
from selenium import webdriver
from bs4 import BeautifulSoup
option = webdriver.ChromeOptions()
# option.add_argument('--headless')
option.add_argument("--log-level=3")
option.add_experimental_option('excludeSwitches', ['enable-logging'])
CDM = ChromeDriverManager(log_level='0')
driver = webdriver.Chrome(CDM.install(), options=option)
tokenurl = "https://poocoin.app/tokens/0xb393d44b9aaecf946925c0198b71f2a5163ce78b"
driver.get(tokenurl)
time.sleep(2)
token = BeautifulSoup( driver.page_source, 'html.parser')
driver.quit()
website = token.find('a', class_='text-danger bg-dark rounded p-2 mt-1 d-inline-block text-decoration-underline')
print(website.text)
两种情况都会有相同的输出：
An unlocked wallet is holding 100.00% of the SMM/BNB LP (click to view LP holders)
因此，您得到 None 作为输出的原因是因为 token 变量中没有足够的数据。您可以将最后一个代码块中的 token 变量与原始代码中的变量进行比较。这是因为如今的网页是动态的，因此我们必须使用可以简化它们的工具。