How to get onblur input id or tabIndex from a cfinput via JavaScript or jQuery?

I have a ColdFusion cfform containing:

<cfinput type="text" name="part1" id="part1" tabIndex="1" onblur="enabled()" >
<cfinput type="text" name="part2" id="part2" tabIndex="2" onblur="enabled()" disabled="disabled" >
<cfinput type="text" name="part3" id="part3" tabIndex="3" onblur="enabled()" disabled="disabled" >

What I want is let input box disabled unless its previous one is not empty, so I done this:

function enabled()
{
    var curIndex = + ( $( " * : focus " ).attr( " tabIndex " ) );
    var curVal = $( ' * : input [ tabIndex=' + curIndex + ' ] ' ).val();
    var nextIndex = curIndex + 1;
    var nextId = $( ' input [ tabIndex = " ' + nextIndex + ' " ] ' ).attr( " id " );
    if ( curVal == "" )
    {
        nextId.setAttribute( ' disabled ', ' disabled ' );
    }
    else
    {
        nextId.removeAttribute( ' disabled ' );
        nextId.focus();
    } 
} 

But I stuck with getting curIndex, it appeared " undefined " when I alerted it.
Any suggestion is appreciated.

What about:

​$('input[type=text][name^=part]').on('blur',function(){​​​​​​​​​​​
    var el = $(this);
    var elNext = el.next('input[type=text][name^=part]');
    if(el.val()!=''){
        elNext.removeAttr('disabled');
    }else{
        elNext.attr('disabled',true);
    }
});

So you don't need the handlers on inputs:

<cfinput type="text" name="part1" id="part1" tabIndex="1" > 
<cfinput type="text" name="part2" id="part2" tabIndex="2" disabled="disabled" > 
<cfinput type="text" name="part3" id="part3" tabIndex="3" disabled="disabled" >

​Demo