js: Validate <select multiple>

aCa

Hi I have a javascript problem. I have a validate script that checks if a field in a form is filled out. F.eks I have a field in a form named form1 : <input type="text" name="name">

On submit I have a js function that return true or false.
Here are parts of that one:

if (document.form1.harlengde.value == "")
{
missing += "Name";
}
if (missing != "")
{
alert(missing);
return false;
}
else return true;

But my problem comes when I have a select field that let you chooce more then one value.
<select mutiple name="hobby[]">
<option>Soccer</option>
<option>Hockey</option>
<option>Baseball</option>
</select>

I have tryed to make a funcion to make sure they select atleast one field. It goes somthing like this:
if (document.form1.hobby[0].value == "")
{
missing += "Hobby";
}
I know this it totaly wrong, but I really dont know how to fix it. I also know there is many ways to check this in php, but I need to use javascript.

Can anyone help me?

PS: There might be some typos here, but this was just an example so the problems isn't typos 🙂

hi-liter

this may work for you...

function chkHobby() {

okHobby = document.form1.hobby.selectedIndex;

if (okHobby < 0) {
	alert ("Please select at least one Hobby.");
	return false;
	}
else {
	return true;

}

}

//-->
</script>
</head>

<body>

<select mutiple name="hobby" size="2">
<option>Soccer</option>
<option>Hockey</option>
<option>Baseball</option>
</select>

</form>

</html>

aCa

It would have worked if I didnt need to get multiple values from the form. Since I need more then one value I must use name="hobby[]", and then the javascript function doesnt work anymore.... :S

Weedpacket

So change the Javascript function to use the form object's element array; something like what's here.