jQuery中未定义的Javascript函数

Question

I have problems with a simple bit of code. I'm trying to take a value from an input field and then do a simple calculation. The calculation is supposed to take place with an onSubmit command and then append it to a p tag.

HTML:

<h1 class="titleHead">Calculator</h1>

<form method="POST" action="#" onSubmit="depositCal()">
  <input type="text" name="money" id="money">
  <input type="submit" value="How much" onSubmit="">
</form>

<div>
  <p class="answer"></p>
</div>

Javascript:

$(document).ready(function() {
    var numberOne = $('#money').val(),
    numberTwo = 4;

    var finalNumber = numberOne + numberTwo;
    function depositCal() {
        $('.answer').append(finalNumber);
     }
})

I get back function not defined when it runs.

I know this is probably very simple but any help would be greatly appreciate.

Answer 1

Try this:

Give your form a name and ID eg 'myForm'

JS

$('#myForm').submit(function(e){
     e.preventDefault();
     var numberOne = $('#money').val();
     var numberTwo = 4;
     var finalNumber = numberOne + numberTwo;
     $('.answer').append(finalNumber);
});

e.preventDefault() - stops the form from submitting (thus refreshing the page) and the function is only fired when submit is clicked.

Addition

numberOne is getting it's value from a form field so it sees it as a string. To prevent this use this line instead:

var numberOne = parseFloat($('#money').val());

Which forces the value to be a (float) number.

Answer 2

You need to declare the function in global scope if you want to use it in inline js

$(document).ready(function() {
    var numberOne = $('#money').val(),
        numberTwo = 4;
    var finalNumber = numberOne + numberTwo;
})
function depositCal() {
    $('.answer').append($('#money').val() + 4);
}

You could also make it a global function by attaching the function to window object.

Answer 3

I think you don't need $(document).ready here and do calculation of finalNumber inside function so that it will give you the correct value of money input, otherwise you will get NaN or empty value-

function depositCal() {
    var numberOne = $('#money').val(),
        numberTwo = 4;
    var finalNumber = numberOne + numberTwo;
    $('.answer').append(finalNumber);
}

Answer 4

您必须将depositCal函数定义排除在$(document).ready() ，因为首先加载整个文档，然后调用$(document).ready()因此，在加载表单时，浏览器会发现depositCal为未定义因为它是在文档完全加载后定义的...因此，将depositCal定义保留在全局范围内