来自“大于"的意外结果.文本输入值的比较 [英] Unexpected result from "greater than" comparison of values from a text input

问题描述

在尝试确定一个值是否大于另一个值时，我遇到了一个奇怪的JavaScript/jQuery数学错误.

I'm experiencing a strange JavaScript/jQuery math bug when trying to determine whether one value is greater than another.

以下是使用jsFiddle到我的代码的链接: http://jsfiddle.net/qxeTj/

Here is a link, using jsFiddle, to my code: http://jsfiddle.net/qxeTj/

$("#Quantity").live("focusout", function() {
    var qty = +$(this).val();
    var stock = +$('#StockLvl').val();
    if (qty > stock) {
        $('#Result').html("<p>Quantity: " + qty + "</p><p>Stock: " + stock + "</p>" + "<p>Not Enough Stock.</p>");
    }
    else if (stock > qty || stock == qty) {
        $('#Result').html("<p>Quantity: " + qty + "</p><p>Stock: " + stock + "</p>" + "<p>Enough Stock.</p>");
    }
});

问题示例:

当我将焦点放在input字段之外时，如果它的值是1或2，则可以正常工作.如果我的值为3, 4, 5, 6, 7, 8, 9，它甚至可以工作.

When I focus out of the input field, if it has a value of 1 or 2, it works fine. It even works if I have a value of 3, 4, 5, 6, 7, 8, 9.

但是问题是当我使用10-19或100-199或1000-1999等中的值时.它说它应该有足够的库存.

But the problem is then when I use values from 10-19 or 100-199 or 1000-1999 and so forth. It say's it has enough stock when it shouldn't.

推荐答案

您正在比较字符串.首先将它们转换为数字.

You're comparing strings. Convert them to numbers first.

var qty = Number( $(this).val() );
var stock = Number( $('#StockLvl').val() );

或

var qty = +$(this).val();
var stock = +$('#StockLvl').val();

或

这种方式对您而言最安全.

This way will be safest in your case.

var qty = parseInt( $(this).val(), 10 );
var stock = parseInt( $('#StockLvl').val(), 10 );

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