Chars control

There are a few syntax errors in your code. Please use the corrected JavaScript below, which includes comments on what has been fixed.

var textFields = document.querySelectorAll('input[type="text"]');  // Use straight quotes
var maxChars = [8, 12];
var player = GetPlayer();

textFields.forEach(function(textField, index) {  // fix "funtion" typo and use standard function syntax
    textField.addEventListener("input", function() {  // fix quotes and typo again
        var maxLength = maxChars[index];
        if (textField.value.length > maxLength) {  // fix "longitud" typo to "length"
            textField.value = textField.value.slice(0, maxLength);

            player.SetVar("Showlayer", true);  // use lowercase player variable and fix quotes
        } else {
            player.SetVar("Showlayer", false);
        }
    });
});

If it still doesn’t work, please upload your slide along with a clear explanation of exactly what you are trying to achieve.