表单提交上的多个输入值

Question

<input type="text" name="Amount" value="100" size="20" maxlength="10" id="textfield7" class="required">

如果我点击提交按钮我想要将值乘以100.有没有办法通过javascript做到这一点???

Answer 1

<script type="text/javascript">
function multiply(){
var val= document.getElementById("textfield7").value;
var newval= val*100;
alert(newval);
}
</script>

<input type="text" name="Amount" value="100" size="20" maxlength="10" id="textfield7" class="required" />
<input type="submit" onClick="multiply();"/>

Answer 2

I would simply write the correct value already multiplied by 100 in the input field. :)

If for any reason this can't be done I would simply do:

<form onsubmit="this[0].value*=100;">
    <input type="text" name="Amount" value="100" size="20" maxlength="10" id="textfield7" class="required">
    <input type="submit">
</form>

Answer 3

var submitButton = document.getElementById("submitButtonId");
submitButton.onclick = function (e) {
  var inputAmount = document.getElementById("textfield7");
  var calculatedAmount = parseInt(inputAmount.value, 10) * 100;
  // do what you wish with calucatedAmount, such as returning false if you don't want to submit
}

Answer 4

Short:

<form onSubmit="document.getElementById('textfield7').value *= 100;">

Cleaner:

<script type="text/javascript">
function multiply(){
  var field = document.getElementById('textfield7');
  field.value = parseInt(field.value) * 100;
}
</script>
<form onSubmit="multiply();">

Answer 5

Yes, but under any normal circumstances it would be the wrong way. Do the math in the server-side code. It is pointless to take even a small risk of getting wrong data (when some data arrives without having been processed by client-side JavaScript).