what does a variable with the string # do javascript? code example

Example 1: js var in string

// in your string you can call your variable like ${myVar}. eg:
var myVar = "blue";
console.log("The sky is " + myVar + ".");
// Output: "The sky is blue."

Example 2: how to use string variable in javascript

<html>
   <head>
      <title>JavaScript Strings</title>
   </head>
   <body>
      <script>
         var re = "java";
         var str = "Learn java";
         if ( str.search(re) == -1 ){
            document.write("Not found!" );
         } else {
            document.write("Found!" );
         }
     </script>
   </body>
</html>