学习 javascript good code

http://www.htmlgoodies.com/primers/jsp/
function counting1(){
    var count = 0;
    count++;

    alert(count);
}

var count = 0;
function counting2(){
    count++;

    alert(count);
}

function validateForm(){
    var radios = document.forms.tutform.elements.color;
    for(var i=0; i<radios.length; i++){
        if(radios[i].checked) return true;
    }
    alert('You must select a color!');
    return false;
}


function validateForm(){
    var email = document.forms.tutform.elements.email.value;
    if(email.indexOf('@')<0){
        alert('There must be an @ sign in your e-mail address');
        return false;
    } else if(email.indexOf('@') != email.lastIndexOf('@')){
        alert('There can not be more than one @ sign in your e-mail address');
        return false;
    } else if(email.indexOf('.')<0){
        alert('There must be at least one period in your e-mail address');
        return false;
    } else if(email.lastIndexOf('.')<email.indexOf('@')){
        alert('There must be at least one period following your @ sign in your e-mail address');
        return false;
    }
    return true;
}
var i=0;
while(i<radios.length){
    if(radios[i].checked) return true;
    i++;
}
alert('You must select a color!');
return false;