CodeIgniter中的表格計算

Question

我想要做的是輸入數量後，餘額和數量應該添加並自動將答案放在平衡。這是一個codeigniter projet。餘額來自數據庫。

<form action="addnew" method="post"> 
    <input type="text" name="io" placeholder="IN_OUT"><br> 
    <input type="date" name="date" placeholder="Date yyyy-mm-dd" value="<?php echo date("Y-m-d") ?>" disabled><br> 
    <input id="qty" type="number" name="qty" placeholder="Quantity"><?php echo $key->ns_balance; ?><br> 
    <input type="text" name="breed" placeholder="Breed"><br> 
    <input type="number" name="es_id" placeholder="Estate"><br> 
    <input type="number" 
      name="balance" 
      placeholder="Balance" 
      value="" disabled> 
    <br> 
    <input type="submit" name="submit" value="Submit"> 
    <input type="reset" name="Reset" value="Reset" 
</form> 

User interface image

Answer 1

嘗試使用此jQuery代碼：

<div id="test"><input id="qty" type="number" name="qty" placeholder="Quantity"><?php echo $key->ns_balance; ?></div> 
<input id="balance" type="hidden" value="<?php echo $key->ns_balance; ?>"> 
$("#qty").on("keyup", function(){ 
var qty = $("#qty").val(); 
var balance= parseInt($("#balance").val()); 

$("#test").text("Balance -"+qty*balance); //you can change the id to place result whereever you want 
});