JavaScript Checkbox Problem

I’ve been having some problems getting the value from a checkbox using JavaScript, and I can’t get anywhere. For some reason it just doesn’t want to get the checkbox value. I’d really appreciate it if anyone can help with this problem.

   	release = document.getElementById('release0');
    	if (release == undefined) {
    		alert('Not Found');
    	} else {
    		alert(release.checked); // Returns true
    	}

        // Conditional Statement - No alert boxes show up
	if (release.checked == true) {
		alert('Release');
	}
	else {
		alert('Do not release');
	}
        alert('Done'); // Never shows up