在jQuery中检测数字是否为INT或FLOAT

Question

I am currently taking input in a text-box and on-submit, I am validating the input, the input needs to be a number greater than 0, it should be integer and not contain decimal point. The problem is I am not able to find any method by which we can detect it is integer or contains decimal point. Here is the code I am using.

    txt[5] = $(this).parents('p').find('input:text').val();
    if (txt[5] == "" || isNaN(txt[5]) || txt[5] <= 0) 
    {
        alert("Incorrect Quantity");
        return false;
    }

Basically as you see I am validating the input given by user, I want to show them a message if the input is wrong, so I am currently using txt[5]%1!=0 to make sure only INT is allowed, but I am open to new answers.

Answer 1

The simplest way is to parse the text as a Number, coerce to integer, and see if they are equal:

var numbertxt5 = Number(txt[5]);
if(numbertxt5 | 0 == numbertxt5) { /* int */
} else if (!isNaN(numbertxt5)) { /* float */
} else { /* not a number */

Answer 2

txt[5] = parseInt($(this).parents('p').find('input:text').val(), 10);

这不会验证数字（请参阅Nirk的答案 ），但是如果它不是整数，它将被转换为1。

Answer 3

That is because JavaScript has only one numerical type called number . It is neither int nor float , but it behaves like both at a time. However, you do have two methods that you can use for this parseInt and parseFloat .

var result = parseInt($(this).parents('p').find('input:text').val());
txt[5] = result;

Using parseFloat is similar. Eg.

var result = parseFloat($(this).parents('p').find('input:text').val());
txt[5] = result;

The second example is not what you want but it is here just for your reference.

UPDATE: @bfavaretto made a good point with using radix which I omitted in parseInt . Have a look at this page for reference http://www.w3schools.com/jsref/jsref_parseint.asp