find the length of a string in google script
<p>I'm trying to make a script for google sheet, who can count a letter in a text. But it seems that .length doesn't work. Anyone who can give directions on where to find the the solution. </p>

<pre><code>    function Tjekkode(tekst , bogstav){
    var test = "";
    // find the length of laengdeTekst
    var laengdeTekst = tekst.length;
    var t = 0;
    // through the text character by character
    for ( var i = 1; i&lt;laengdeTekst ; i++) {

     var test = tekst.substr(i,1);
     if (test == bogstav) {
      // if the letter is found, it is counted up
      // REMEMBER == means compare
      var t = t + 1;
     }
    }
    // returns percent appearance of the letter
    Return = t / længdeTekst * 100
    }
</code></pre>

<p>Thanks in advance</p>