function set_elem_error(elem_id)
{
    elem = document.getElementById(elem_id);
    elem.style.backgroundColor = 'yellow';
    elem.style.border = '1px solid red';
    elem.style.color = 'red';
    elem.style.fontWeight = 'bold';        
}

function set_elem_valid(elem_id)
{
    elem = document.getElementById(elem_id);
    elem.style.backgroundColor = '#bcf4c5';
    elem.style.border = '1px solid #499856';
    elem.style.color = '#499856';
    elem.style.fontWeight = 'bold';
}
   
function set_elem_normal(elem_id)
{
    elem = document.getElementById(elem_id);
    elem.style.backgroundColor = '#ffffff';
    elem.style.border = '1px solid black';
    elem.style.color = 'black';
    elem.style.fontWeight = 'normal'; 
}

function check_char(elem_id,event)
{
    elem = document.getElementById(elem_id);
    current = elem.value;
           
    switch (elem_id)
    {
        
        case 'pno_part1':
            if (current.length == 5)
            {
                if (!current.match(/[0-9]{5}/))
                {
                    set_elem_error(elem_id);
                    return;                        
                }

                if (document.getElementById('pno_part2').value.length == 6 && document.getElementById('pno_part3').value.length ==4)
                {
                	goto_url = 'processing/check_part_number.php?type=max&partno='+
                                        current+'-'+
                                        document.getElementById('pno_part2').value+'-'+
                                        document.getElementById('pno_part3').value;
                                        
                    response_value = call_returning_response(goto_url,null,'dummy');
                    if (response_value > 0)
                    {
                        set_elem_valid(elem_id);
                        set_elem_valid('pno_part2');
                        set_elem_valid('pno_part3');
                        return;                            
                    }                                             
                }

                return autoTab(elem,5,event);                    
            }
            break;
            
        case 'pno_part2':
            if (current.length == 6)
            {
                if (!current.match(/[0-9]{6}/))
                {
                    set_elem_error(elem_id);
                    return;
                }

                if (document.getElementById('pno_part1').value.length == 5 && document.getElementById('pno_part3').value.length == 4)
                {
                	goto_url
                    response_value = call_returning_response('processing/check_part_number.php?type=max&partno='+
                                        document.getElementById('pno_part1').value+'-'+
                                        current+'-'+
                                        document.getElementById('pno_part3'),null,'dummy');
                                        
                    if (response_value > 0)
                    {
                    	alert('here2');
                        set_elem_valid(elem_id);
                        set_elem_valid('pno_part3');
                        set_elem_valid('pno_part1');
                        return;
                    }                                                
                }

                return autoTab(elem,6,event);
            }
            break;
            
        case 'pno_part3':
            if (current.length == 4)
            {
                if (!current.match(/([0-9]{4})|([A-Za-z]{1}[0-9]{3})/))
                {
                    set_elem_error(elem_id);
                    return;                          
                }
                
                if (document.getElementById('pno_part2').value.length == 6 && document.getElementById('pno_part1').value.length == 5)
                {
                    response_value = call_returning_response('processing/check_part_number.php?partno='+
                                        document.getElementById('pno_part1').value+'-'+
                                        document.getElementById('pno_part2').value+'-'+
                                        current,null,'dummy');
                    
                    if (response_value > 0)
                    {
                        set_elem_valid(elem_id);
                        set_elem_valid('pno_part2');
                        set_elem_valid('pno_part1');
                        return;                            
                    }
                    set_elem_error(elem_id);
                    set_elem_error('pno_part2');
                    set_elem_error('pno_part1');
                    return;
                }
                
                return autoTab(elem,4,event);                
            }
            break;            

    }
    
    if (current.match(/\w{0,}/))
    {
        set_elem_normal(elem.id);
    }        
}