Js Get Varible Defined In Script Tag (google Extension)

I've got a small problem. I want to read a var defined inside tag in DOM. I can access it via: var script = document.querySe

Solution 1:

Content script runs in isolated world so it cannot access the page variables directly.

• a literal numeric value can be extracted with a regexp:

  var scriptText = document.getElementById('foo').textContent;
  var x = parseFloat(scriptText.match(/var x\s*=\s*(-?(\d*\.)?\d+(e-?\d+)?)|$/)[1]);
  

• a global page variable of any JSON-ifiable type can be accessed from a script element because it runs in page context:

  functiongetPageVariable(name) {
    returnnewPromise(resolve => {
      window.addEventListener(`${chrome.runtime.id}-variable`, e => {
        resolve(JSON.parse(e.detail));
      }, {once: true});
      var script = document.createElement('script');
      document.documentElement.appendChild(script).text = `
        window.dispatchEvent(new CustomEvent('${chrome.runtime.id}-variable', {
          detail: JSON.stringify(window.${name})
        }))`;
      script.remove();
    });
  }  
  

  Usage:

  getPageVariable('x').then(x => {
    // do something with x
  });
  

  Depending on the page CSP, a different method of code injection may be required.

Solution 2:

Once you're within the scope you should be able to access your variable from wherever you want...

<scriptid="foo">var x = 1</script><divid="test"></div><script>document.getElementById("test").innerHTML = x;
</script>