SelectBox validates in IE but not in FF

[Alendrin]

It's a simple selectbox, i've scoured the web for a few hours now but have given up, it validates in IE but not FF

form:

<form name="form1">

<label><span class="style19">Mileage*:</span></label>
<select name="MySelect">
<option value="none">Please Select</option>
<option value="0-25">0-25</option>
<option value="26-50">26-50</option>
<option value="51-75">51-75</option>
<option value="76-100">76-100</option>
<option value="over100">Over 100</option>
</select><br>

<input type="button" name="Button" value="clear" onClick="blanks()">
<input type="button" name="Button" value="Submit" onClick="validate()">
</form>



Javascript:

function validate()
{

MySelect = document.form1.MySelect.options[form1.MySelect.selectedIndex].value

if (document.form1.MySelect.options[form1.MySelect.selectedIndex].value=='none')

{
alert("Please enter your mileage")
}
else
{
alert("thank you")
}

}

[Dormilich]

missing semi-colons and missing document.
try
function validate()
{
var MySelect = document.form1.MySelect.value;

if ('none' == MySelect) {
alert("Please enter your mileage");
}
else {
alert("thank you");
}
}