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HTML

              
                
              
            
!

CSS

              
                body {
  font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif;
  
  --html:(
    <h1>Hello ${data.name}!</h1>
    <p>This page was constructed entirely within the CSS file. That includes all the data, markup, scripts, and also styles.</p>
    <p>For more information, see the <a href="https://github.com/scottkellum/CJSS">CJSS</a> repo on Github.</p>
    <p>click the items below to toggle them. This is to illustrate component-level JS in the CSS file.</p>
    <nav>Nav heading</nav>
  );
  --data:(
    name:'world',
  );
}

nav {
  --data:(
    links: ['one', 'two', 'three'],
  );
  --html:(
    <h2>${yield}</h2>
    <div class="item">${data.links[0]}</div>
    <div class="item">${data.links[1]}</div>
    <div class="item">${data.links[2]}</div>
  );
}

nav .item {
  cursor: pointer;
  --js:(
    function toggle() {
      this.classList.toggle('active');
    }
    this.addEventListener('click', toggle );
  );
}
nav .item.active {
  color: red;
}

/* Run a script like typetura.js */
script {
  --data:(
    say: 'Hello world!'
  );
  --js:(
    console.log(data.say);
  );
}
              
            
!

JS

              
                (() => {

  /**
   * Get value of a rule's property and remove surrounding parentheses.
   * @param rule The CSSStyleRule, which to select from.
   * @param propertyName The name/key which to select.
   **/
  function getPureProperty(rule, propertyName) {
    const raw = rule.style.getPropertyValue(propertyName);
    return raw.trim().slice(1, -1);
  }

  /**
   * Runs CJSS rules - CSS rules with the special properties --html, --js and --data.
   * @param rules An array of CJSS rules.
   **/
  function cjss(rules) {
    for (let rule of rules) {
      const ruleName = rule.constructor.name;

      // Handle imports (recursive)
      if (ruleName === 'CSSImportRule') {
        const importedRules = rule.styleSheet.cssRules;
        cjss(importedRules);
      }

      else if (ruleName === 'CSSStyleRule') {
        const selector = rule.style.parentRule.selectorText;
        const elements = document.querySelectorAll(selector);

        let js = getPureProperty(rule, '--js');
        let html = getPureProperty(rule, '--html');
        let data = getPureProperty(rule, '--data');

        if (data) {
          data = eval(`({ ${ data } })`);
        }

        if (html) {
          for (let element of elements) {
            const yield = element.innerHTML;

            // eval could be removed with a "shallow parser".
            element.innerHTML = eval(`\`${ html }\``);
          }
        }

        if (js) {
          if (selector === 'script') {
            eval(js);
            continue;
          }

          // There is a lot of room for optimization here.
          for (let n = 0; n < elements.length; n++) {
            eval(js.replace(/this/g, `document.querySelectorAll('${ selector }')[${ n }]`));
          }
        }
      }
    }
  }

  /**
   * Plug every stylesheet in the document into the cjss function.
   */
  function initialize() {
    for (let sheet of document.styleSheets) {
      const rules = sheet.rules || sheet.cssRules;

      if (!rules || !rules.length) continue;
      cjss(rules);
    }
  }

  document.addEventListener('DOMContentLoaded', initialize);
})();
              
            
!
999px

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