锚元素内的输入元素

Question

I have a form like this:

<form id="cars" action="file.php" method="post">
<a href="#" onclick="document.getElementById('cars').submit();"><input type="hidden" value="ford" name="model" />Ford</a>
<a href="#" onclick="document.getElementById('cars').submit();"><input type="hidden" value="toyota" name="model" />Toyota</a>
</form>

However, the $_POST['model'] gave error "Undefined index: model". What's wrong with that?

Answer 1

You only need to have one hidden input outside your a elements. It will get its value based on the element clicked just before submit(). So your form will look like this:

<form id="cars" action="file.php" method="post">
    <a href="#" onclick="submitModel('ford')">Ford</a>
    <a href="#" onclick="submitModel('toyota')">Toyota</a>
    <input id="hiddenModel" type="hidden" name="model" value="ford" />
</form>

And your javascript:

function submitModel(mdl) {
    document.getElementById('hiddenModel').value = mdl;
    document.getElementById('cars').submit();
}

jsfiddle DEMO