moved to src folder

src/content.js

@@ -0,0 +1,48 @@
+// Get stored word list from chrome storage
+chrome.storage.local.get(["vocabulary", "kanji", "validUserLevel"], (data) => {
+    // The users level is not valid, e.g. it exceeds the maximum allowed level
+    // WaniKani requires that devs check if users are actually allowed to access content of this level
+    if(!data.validUserLevel)
+        return
+
+    const vocabulary = data.vocabulary
+    const kanji = data.kanji
+
+    // Fetch all <ruby> tags on the website
+    var rubyTags = document.body.getElementsByTagName("ruby")
+
+    for(let tag in rubyTags)
+    {
+        // Copy the ruby element into a new ruby element so we can modify it
+        // without modifying the website
+        var ruby = document.createElement("ruby")
+        ruby.innerHTML = rubyTags.item(tag).innerHTML
+
+        // Remove all tags (except for <rb>)
+        while(ruby.lastElementChild)
+        {
+            if(ruby.lastElementChild.tagName.toLowerCase() === "rb" ||
+                ruby.lastElementChild.tagName.toLowerCase() === "span")
+            {
+                ruby.innerHTML = ruby.lastElementChild.innerHTML
+                break
+            }
+
+            ruby.removeChild(ruby.lastElementChild)
+        }
+
+        // If the contents of the <ruby> tag are in the word list, remove the <rt> tag
+        if(vocabulary.includes(ruby.innerText) || kanji.includes(ruby.innerText))
+        {
+            var rtTag = rubyTags.item(tag).getElementsByTagName("rt").item(0)
+            try 
+            {
+                rtTag.parentNode.removeChild(rtTag)
+            } catch(error)
+            {
+                console.error(error)
+                console.log(rubyTags.item(tag))
+            }
+        }
+    }
+})