Why doesn't this script work?

Why doesn't this script work?

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span id="price_here" hidden="hidden">600</span><span id="sum_here">600</span> </button>◀<input type="number" value="1" onchange="check_qty($(this),1,100);" name="qty" id="qty" value="<? echo $qty ?>"></input>▶<button onclick="qplus('#qty', 100);" id="plus">^__i></button> <span id="sum_here1"></span>^__i id="mlus">

<script>
$('#price_here').each(function() {
     this.textContent *= 2;
});

function qminus(el, min) {
     var e = $(el);
     var compare = parseInt(e.val());
     var i = ((compare - 1) < min) ? min : compare - 1;
     e.val(i);
     show_price(i);
}
  function qplus(el, max) {
     var e = $(el);
     var compare = parseInt(e.val());
     var i = ((compare + 1) > max) ? max : compare + 1;
     e.val(i);
     show_price(i);
}
  function check_qty(el, min, max) {
     var compare = parseInt(el.val());
     if (compare < min) {
         el.val(min);
         alert(min + ' is minimal qty');
     }
     if (compare > max) {
         el.val(max);
         alert(max + ' is maximum qty');
     }
     show_price1(el.val());
}
  function show_price(ch) {
     var sum = $('#price_here').html() * ch,
           coeff = +ch > 1 ? 0.02 : 0;
     $('#sum_here').html(sum * (1 - coeff));
     $('#sum_here1').html(sum * coeff);
}
</script>

<script>
$('#price_here').each(function() {
     this.textContent *= 2;
});

function qminus(el, min) {
     var e = $(el);
     var compare = parseInt(e.val());
     var i = ((compare - 1) < min) ? min : compare - 1;
     e.val(i);
     show_price(i);
}
  function qplus(el, max) {
     var e = $(el);
     var compare = parseInt(e.val());
     var i = ((compare + 1) > max) ? max : compare + 1;
     e.val(i);
     show_price(i);
}
  function check_qty(el, min, max) {
     var compare = parseInt(el.val());
     if (compare < min) {
         el.val(min);
         alert(min + ' is minimal qty');
     }
     if (compare > max) {
         el.val(max);
         alert(max + ' is maximum qty');
     }
     show_price1(el.val());
}
  function show_price(ch) {
     var sum = $('#price_here').html() * ch,
           coeff = +ch > 1 ? 0.02 : 0;
     $('#sum_here').html(sum * (1 - coeff));
     $('#sum_here1').html(sum * coeff);
}
</script>