如何在數字框中顯示覆選框和下拉列表的產品

Question

這裏是我的目錄代碼。希望顯示覆選框的值乘以下拉列表的值並將產品輸出到。只需使用html和javascript代碼即可。

<table align=center border=1> 
<tr colspan=3> 
<td colspan=3><h2>Specialty Cakes</h2></td> 
</tr> 
<tr> 
<td><img src=special\blackforest_small.jpg valign=center-right><br><center>Black Forest</td> 
<td>Chocolate sponge layered with sugar syrup and Kirsch flavouring, white mousse and dark sweet cherries.</td> 
<td><input type="checkbox" id="check1" name="check1" value="550.00"onclick="product1()">Buy P550.00</input><br><input type="number" id="total1" name="total1" value="P0.00"size="8"></input><br> 
QTY: <select id="qty1" name="qty1" onchange="product1()"> 
<option value="1">1</option> 
<option value="2">2</option> 
<option value="3">3</option> 
<option value="4">4</option> 
<option value="5">5</option> 
<option value="6">6</option> 
<option value="7">7</option> 
<option value="8">8</option> 
<option value="9">9</option> 
</select> 
</td> 
</tr> 

</table> 
<script> 
var m = document.getElementById("check1").checked; 
function product1(){ 
var x = document.getElementById("check1").value; 
var y = document.getElementById("qty1").value; 
var z = 0; 
if (m = true){ 
z = "P" + x * y; 
} 
document.getElementById("total1").value = z; 
} 
</script> 

Answer 1

你有ID共1作爲一種=號碼輸入你 - 但你分配給它P0.00的文本值更改其類型爲文本，它會工作，或給它一個數值。