脚本的目的是什么?标签服务在<noscript>标签

What purpose does a <script> tag serve inside of a <noscript> tag?

本文关键字:标签 noscript 服务 是什么 脚本      更新时间:2023-09-26

我最近一直在"查看源代码"的网站上有有趣的设计和内容。其中一个网站,Squarespace,在<noscript>标签里面有<script>标签块,像这样:

<!-- Page is at: http://squarespace.com -->
...
...
<noscript id="inline-deps">
  <link rel="stylesheet" type="text/css" href="//cloud.typography.com/7811972/758964/css/fonts.css" />
  <script type="text/javascript" src="https://static.squarespace.com/static/ta/5134cbefe4b0c6fb04df8065/7400/assets/logomark/logomark.min.js?37"></script>
  <link rel="stylesheet" href="https://static.squarespace.com/static/ta/5134cbefe4b0c6fb04df8065/7400/assets/logomark/logomark.min.css?37" type="text/css" />
</noscript>
...
...

这让我觉得很奇怪,并让我谷歌信息,看看是否有某种隐藏的功能/目的,这样一个奇怪的HTML位,但无济于事。是否有某种目的有<script>标签内的<noscript>元素,或者这只是一个坏的HTML的例子?

我在他们的代码中做了一些搜索,找到了这个代码片段(我已经清理了它,使它更易于阅读):

var DepLoader = (function () {
  function init() {
    var dependencies = document.getElementById("inline-deps");
    if (!dependencies || JS.hasClass(document.body, "deps--loaded")) {
      webfontsReady();
    } else {
      var html = dependencies.innerText || dependencies.textContent;
      JS.addClass(document.body, "deps--loaded");
      processRaw(html);
    }
  }
  function isListed(a, b) {
    for (var i = 0; i < b.length; i++) {
      if (a.indexOf(b[i]) !== -1) {
        return true;
      }
    }
    return false;
  }
  function webfontsReady() {
    JS.fireCustom("webfontsReady");
  }
  function processRaw(html) {
    var el = document.createElement("div");
    el.innerHTML = html;
    var scripts = el.querySelectorAll("script");
    var styles = el.querySelectorAll("link");
    var common, signup, dialog, systemPage, commerce;
    var others = [];
    var inline = [];
    var styleWhiteList = ["site.css", "dialog-", "signup-", "logomark"];
    var scriptBlackList = ["management-", "ckeditor-"];
    for (var i = 0; i < styles.length; i++) {
      var style = styles[i];
      if (style.href.indexOf("fonts.css") !== -1) load(style, webfontsReady);
      if (isListed(style.href, styleWhiteList)) load(style);
    }
    for (var i = 0; i < scripts.length; i++) {
      var script = scripts[i];
      var src = script.src;
      if (!src && script.getAttribute("data-sqs-type") !== "dynamic-assets-loader" && script.innerHTML.indexOf("SQUARESPACE_ROLLUPS") === -1) {
        eval(script.innerHTML);
      }
    }
    if (window.SQUARESPACE_ROLLUPS) {
      for (var key in SQUARESPACE_ROLLUPS) {
        var rollup = SQUARESPACE_ROLLUPS[key];
        var js = rollup.js;
        var css = rollup.css;
        if (key.indexOf("common") !== -1) {
          common = js;
        } else if (key.indexOf("commerce") !== -1) {
          commerce = js;
        } else if (key.indexOf("signup") !== -1) {
          signup = js;
        } else if (key.indexOf("dialog") !== -1) {
          dialog = js;
        } else if (key.indexOf("system-page") !== -1) {
          systemPage = js;
        } else if (key) {
          others = others.concat(js);
        } else {
          inline = inline.concat(js);
        }
      }
    }
    for (var i = 0; i < scripts.length; s++) {
      var script = scripts[i];
      var src = script.src;
      if (!isListed(src, scriptBlackList)) {
        if (src.indexOf("common-") !== -1) {
          common = script;
        } else if (src.indexOf("commerce-") !== -1) {
          commerce = script;
        } else if (src.indexOf("signup-") !== -1) {
          signup = script;
        } else if (src.indexOf("dialog-") !== -1) {
          dialog = script;
        } else if (src.indexOf("system-page-") !== -1) {
          systemPage = script;
        } else if (src) {
          others.push(script);
        } else {
          inline.push(script);
        }
      }
    }
    function loadOthers() {
      for (var i = 0; i < inline.length; i++) {
        if (inline[i].getAttribute("data-sqs-type") !== "dynamic-assets-loader") {
          load(inline[a]);
        }
      }
      for (var i = 0; i < others.length; i++) {
          load(others[i]);
      }
      JS.fireCustom("dependenciesLoaded");
    }
    var loadSystemPage = load.bind(this, systemPage, loadOthers, "system page");
    var loadSignup = load.bind(this, signup, loadSystemPage, "signup");
    var loadCommerce = load.bind(this, commerce, loadSignup, "commerce");
    var loadDialog = load.bind(this, dialog, loadCommerce, "dialog");
    var loadCommon = load.bind(this, common, loadDialog, "common");
    loadCommon();
  }
  function load(tag, callback, label) {
    var head = document.head;
    if (Array.isArray(tag)) tag = { nodeName: "SCRIPT", src: tag[0] };
    if (!tag) {
      if (callback) callback();
      return;
    }
    if (tag && (tag.src || tag.href)) {
      var child;
      if ("SCRIPT" === tag.nodeName) {
        child = document.createElement("script");
        child.src = tag.src;
        if (child.src.indexOf("combo") !== -1) {
          callback = function () {
            Y.Squarespace.FrontSite.Core.domReady(true)
          };
        }
      } else {
        if ("LINK" === tag.nodeName && "stylesheet" === tag.rel) {
          child = document.createElement("link");
          child.href = tag.href;
          child.rel = "stylesheet";
          child.tyle = "text/css";
        }
        if (child) {
          child.onload = callback;
          head.appendChild(child);
        }
      }
    } else {
      try {
        eval(tag.innerHTML);
      } catch (e) {}
    }
  }
  return { init: init, webfontsReady: webfontsReady };
})();
如您所见,<noscript>标签的ID为#inline-deps,它在代码(第3行)中被引用,以异步和按需加载依赖项。

他们可能使用<noscript>元素,因为它允许他们直接访问DOM元素,而不是必须将其放在字符串或注释中(我认为这特别糟糕,因为注释不意味着实际信息),然后解析它。它还可以防止脚本和CSS样式的执行,直到特别加载。

我个人认为这是对<noscript>标签的滥用。我甚至不确定它是否是有效的HTML5代码。在可行的情况下,应该使用其他方法,比如在JavaScript对象中使用脚本加载器声明依赖关系。
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