how to get previous values while do on change in dropdown

how to get previous values while do on change in dropdown

eg:
in my drop down i selected as 4  then i going to change the drop down to 5
i want to get previous values (4) also .

some condition the new value is duplicate then i need to set the old (previous ) value
LVL 20
Sathish David  Kumar NArchitectAsked:
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vr6rCommented:
You'll need to save the previous value to a js variable since the normal change events occur after the new value has already been set.  Here's an example:

<select id="dropdown">
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
</select>

<script>
$(function(){
    var previous;
    
    $('#dropdown').focus(function(e){
       previous = $(this).val(); 
    });
    
    $('#dropdown').change(function(e){
        //use 'previous' var to perform whatever logic you need here
        alert("previous value = " + previous + ", current value = " + $(this).val());
        
        //set previous to current selection value now in case 
        //user makes another selection without the dropdown losing focus
        previous = $(this).val();
    });
});
</script>

Open in new window


fiddle: http://jsfiddle.net/6pg1L2nk/2/

Hope this helps.
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