Question

Why isn’t dec() decreasing the value?

<div id="variableTest">8</div>
<label id="incButton" onclick="inc()">+</div> </br>   
<label id="decButton" onclick="dec()">-</div> </br>
    ​

function dec() {
    var testDec = document.getElementById("variableTest").innerHTML;
    testDec--;
}

function inc() {
    var testInc = document.getElementById("variableTest").innerHTML;
    testInc++;
}​

http://jsfiddle.net/fv6VA/8/

Answer 1

element.innerHTML returns a string, not a number. You should use something like this:

var element = document.getElementById("variableTest");
element_number = parseFloat(element.innerHTML);
element_number++;
element.innerHTML = element_number;