Question

function changeSize( fontsize ) {

    var body = document.getElementById("body");
        var font = fontsize + "-font";
        body.className = font;

}


<input type="button" onclick="changeSize(small)" value="Small" /> 

Firefox console keeps saying that small is undefined. What am I doing wrong?

Answer 1

You’re passing in small as a variable, not a string to put into the DOM. Javascript is looking for the var small to be defined somewhere, and it’s not. You need to pass in a string as an argument.

Try onclick="changeSize('small')"