To select the option by its text, get a reference to the select, iterate over the options looking for the one with text "Holden", then either set the select's selectedIndex property to the index of the option, or set the option's selected property to true. e.g.
function setSelectedByText(id, text) {
var select = document.getElementById(id);
var options = select && select.options;
var opt;
for (var i=0, iLen=options.length; i++) {
opt = options[i];
if (opt.text == text) {
opt.selected = true;
// or
select.selectedIndex = i;
}
}
}
For the record, the value of the select element is the value of the selected option, or, if the selected option has no value, it's text. However, IE gets it wrong and returns "" if the option has no value.
Also, if you don't want to use getElementById, you can use:
var select = document.formName.selectName;
Noting that the select element must have a name to be successful (i.e. for its value to be returned when the form it's in is submitted).