selectedIndex - javascript on Google Chrome

Can any开发者_Python百科one please tell me why doesn't this work on Google Chrome:

val = document.form.option[document.form.selectedIndex].value;

How should I get around this so that other browsers (like IE and FF) don't get screwed up.

Many thanks in advance.

Try this:

<select id="option">
....
</select>

then

val = $('#option').val();

It's because you're not actually selecting a form element. It should be something like this (I pretend that your select is named myselect):

var formElement=document.getElementsByName("myselect")[0]; /* Select the form element */
var val=formElement.options[formElement.selectedIndex].value; /* Grab its value */

Here's an example in action.

From jQuery's page

$('select.foo').val(); // get the value from a dropdown select even easier

jQuery (1.4.2) code for function val when element is a select

if ( jQuery.nodeName( elem, "select" ) ) {
    var index = elem.selectedIndex,
        values = [],
        options = elem.options,
        one = elem.type === "select-one";

    // Nothing was selected
    if ( index < 0 ) {
        return null;
    }

    // Loop through all the selected options
    for ( var i = one ? index : 0, max = one ? index + 1 : options.length; i < max; i++ ) {
        var option = options[ i ];

        if ( option.selected ) {
            // Get the specifc value for the option
            value = jQuery(option).val();

            // We don't need an array for one selects
            if ( one ) {
                return value;
            }

            // Multi-Selects return an array
            values.push( value );
        }
    }

    return values;
}