Using a switch with strings in JavaScript

Question

My switch statement is not working properly when analysing a string variable.

The output and input are both <textarea>'s.

HTML

<form name="interface">
  <textarea name="output" rows="20" cols="100"></textarea><br>
  <textarea name="input" rows="1" cols="100" onKeyDown="thinkInput(event);"></textarea>
</form>

JavaScript

function thinkInput(e)
{
    if (e.keyCode == 13)
    {
        sInput = document.interface.input.value;
        document.interface.output.value += sInput;
        aInput = sInput.split(" ");

        switch (aInput[0])
        {
            case "say":
                textOut("You say \""+sInput.substring(aInput[0].length + 1)+"\"");
                break;
            case "move":
                move(aInput[1]);
                break;
            default:
                thinkFail();
                break;
        }
        document.interface.input.value = null;
        alert(aInput[0]);
    }
}

I can see in my alert() at the end that the case is either "say" or "move".

The first time I try to "say mudkipz" or "move around", everything works as I want it, but after that everything I type, thinkFail() fires.

Answer 1

Your code isn't executing due to a new line that appears above the command prompt and the split array doesn't contain the reference first word on [0] value. Don't know why, even though you're clearing the value of input.

Since you'll be needing only one line on this input, I suggest using <input type="text" onKeyDown="thinkInput(event);"/> to avoid getting new lines on enter.

JavaScript

this.thinkInput = function (e)
{   
    ...

    if (e.keyCode == 13)
    {   
        /* Prevent submitting form on Enter */ 
        e.preventDefault();

        var command, commands;

        command = cmd.value;
        commands = command.split(' ');
        /* Clear input field */
        cmd.value = '';

        /* commands[0] will always have reference
           to the first word in textfield */
        switch (commands[0])
        {
            ...
        }
    }
}

Here is a little fiddle I threw together from your code: http://jsfiddle.net/npx86/1/

Hope this helps!