Allow language attribute to be changed after being unset

Author: WebCoder49

code-input.js

@@ -773,13 +773,15 @@ var codeInput = {
                             if (code.classList.contains(`language-${newValue}`)) break; // Already updated
                         }
 
+                        if(oldValue !== null) {
+                            // Case insensitive
+                            oldValue = oldValue.toLowerCase();
 
-                        // Case insensitive
-                        oldValue = oldValue.toLowerCase();
-
-                        // Remove old language class and add new
-                        code.classList.remove("language-" + oldValue); // From codeElement
-                        code.parentElement.classList.remove("language-" + oldValue); // From preElement
+                            // Remove old language class and add new
+                            code.classList.remove("language-" + oldValue); // From codeElement
+                            code.parentElement.classList.remove("language-" + oldValue); // From preElement
+                        }
+                        // Add new language class
                         code.classList.remove("language-none"); // Prism
                         code.parentElement.classList.remove("language-none"); // Prism
 

tests/hljs.html

@@ -41,7 +41,7 @@ <h4><a href="prism.html">Test for Prism.js</a></h4>
 
     <details id="collapse-results"><summary>Test Results (Click to Open)</summary><pre id="test-results"></pre></details>
     <form method="GET" action="https://google.com/search" target="_blank">
-        <code-input language="JavaScript" name="q">console.log("Hello, World!");
+        <code-input name="q">console.log("Hello, World!");
 // A second line
 // A third line with &lt;html> tags</code-input>
         <input type="submit" value="Search Google For Code"/>

tests/prism.html

@@ -43,7 +43,7 @@ <h4><a href="hljs.html">Test for highlight.js</a></h4>
 
     <details id="collapse-results"><summary>Test Results (Click to Open)</summary><pre id="test-results"></pre></details>
     <form method="GET" class="line-numbers" action="https://google.com/search" target="_blank">
-        <code-input language="JavaScript" name="q">console.log("Hello, World!");
+        <code-input name="q">console.log("Hello, World!");
 // A second line
 // A third line with &lt;html> tags</code-input>
         <input type="submit" value="Search Google For Code"/>

tests/tester.js

@@ -241,9 +241,9 @@ console.log("I've got another line!", 2 < 3, "should be true.");`);
     if(!isHLJS) {
         // Highlight.js has autodetect plugin that should make this fail, so don't run these tests with it.
         testAssertion("Core", "Language attribute Initial value", 
-            codeInputElement.codeElement.classList.contains("language-javascript")
+            !codeInputElement.codeElement.classList.contains("language-javascript")
             && !codeInputElement.codeElement.classList.contains("language-html"), 
-            `Language set to JavaScript but code element's class name is ${codeInputElement.codeElement.className}.`);
+            `Language unset but code element's class name is ${codeInputElement.codeElement.className}.`);
 
         codeInputElement.setAttribute("language", "HTML");