How to get decimal value when user input decimal?

<label>Insert value :</label>
<a class="bold scoreClick">Click to change score</a>																			<div class="bold scoreInputdiv" style="display:none;">
<input class="bold scoreInput" type="number" step="any" size="2" id="score_final_a" value="'.$data['final_score_sectiona'].'"/> /50 
<button type="button" class="btn btn-success btnFinalASave">Save</button></div>

$('.scoreClick').on("click", function (e){
	e.preventDefault();
	var tt = $(this).next('.scoreInputdiv');
	tt.show();
	$(this).hide();
	tt.children('.scoreInput').focus().select();
});
//FINAL
	$('.btnFinalASave').on("click", function (e){
	e.preventDefault();
	var score = $(this);
	var a = parseFloat($(score).prev('.scoreInput').val().trim()) || 0;
	var assessment_performance_id = <?php echo $data['id'];?>;
	var score_final_b = $('#score_final_b').val();
	var score_final_c = $('#score_final_c').val();
			
	if (a > 0){
		$(score).prev('.scoreInput').val(a.toString());
	}
	else{
		$(score).prev('.scoreInput').val('');
	}
			
	$.ajax({
		type: 'GET',
		url: './ajax/update_final_score_assessment.php',
		data: {
			'assessment_performance_id' : assessment_performance_id,
			'score_final_a' : a.toString(),
			'score_final_b' : score_final_b,
			'score_final_c' : score_final_c
		},
			contentType: "application/json; charset=utf-8",
			dataType: "json",
			beforeSend: function(){
					
		},
		    success: function(data){},
			error: function(message){
				//response([]);
				//console.log(message);
			},
			complete: function(){
				if (a > 0){	
						 
    $(score).parent('.scoreInputdiv').prev('a').html(a.toString());
			}
	else{
	   $(score).parent('.scoreInputdiv').prev('a').html('-');
	}
					
	$(score).parent('.scoreInputdiv').prev('a').show();
	$(score).parent('.scoreInputdiv').hide();
	}
 });
});

<pre><?php
$data = false;
if(isset($_GET['assessment_performance_id'])) {
	include_once '../config/general.php';
	include_once '../config/db.php';
	include_once '../config/myApp.php';
	
	$assessment_performance_id = (int)$_GET['assessment_performance_id'];
	//$score_final_a = (int)$_GET['score_final_a'];
	//$score_final_b = (int)$_GET['score_final_b'];
	//$score_final_c = (int)$_GET['score_final_c'];
	
	$score_final_a = 0;
	if (isset($_GET['score_final_a'])){
		$score_final_a = (int)$_GET['score_final_a'];
	}

	$score_final_b = 0;
	if (isset($_GET['score_final_b'])){
		$score_final_b = (int)$_GET['score_final_b'];
	}

	$score_final_c = 0;
	if (isset($_GET['score_final_c'])){
		$score_final_c = (int)$_GET['score_final_c'];
	}
	
	//$final_overall_score = 0;
	$final_overall_score = $score_final_a + $score_final_b + $score_final_c;
	
	$validProcess = true;
	
	if ($validProcess){
		$data = true;

		if ($score_final_a){

			$mySQL = 'UPDATE assessment_performance SET 
			final_score_sectiona = "'.number_format((float)$score_final_a,1,'.','').'",
			final_overall_score = "'.number_format((float)$final_overall_score,1,'.','').'"
			WHERE id = '.$assessment_performance_id;
			mysql_query($mySQL);
		}
		if ($score_final_b){

			$mySQL = 'UPDATE assessment_performance SET 
			final_score_sectionb = "'.number_format((float)$score_final_b,1,'.','').'",
			final_overall_score = "'.number_format((float)$final_overall_score,1,'.','').'"
			WHERE id = '.$assessment_performance_id;
			mysql_query($mySQL);
		}

		if ($score_final_c){

			$mySQL = 'UPDATE assessment_performance SET 
			final_score_sectionc = "'.number_format((float)$score_final_c,1,'.','').'",
			final_overall_score = "'.number_format((float)$final_overall_score,1,'.','').'"
			WHERE id = '.$assessment_performance_id;
			mysql_query($mySQL);
		}
			
	}

}

header("Content-type: text/x-json");
print json_encode($data);
?>