Question

Is it possible on <select> get previously selected value or prevent default somehow? For example i have

<select id="select_site" name="sites" selectedindex="0">
<option value="">Please select site</option>
<option value="4">first</option>
<option value="5" selected="selected">second</option>
<option value="8">third</option>
</select>

So if selected option with null value i need to restore previously selected second value.

Answer 1

You can bind a change event handler to the element and store the new value in a variable. If the value is an empty string, set it to whatever is in the variable:

$('#select_site').change(function() {
    if (this.value === '') {
        this.value = $(this).data('previous_value');
    }
    else {
        $(this).data('previous_value', this.value);
    }
}).triggerHandler('change'); // <- trigger change event to get initial value

DEMO