哪种方法可以过滤文本字段的数值？ [英] Which is the proper way of filtering numeric values for a text field?

问题描述

我正在开发一个文本字段，使用那种不允许您输入数字值以外的验证。因此，我的初始代码看起来很简单，与此类似：

I'm working on a textfield working with the kind of validation that wouldn't let you enter other than numeric values. As so, my initial code looked quite simple and similar to this:

$(textField).onKeyPress(function(e) {
    if (e.which < 48 && e.which > 57)
        e.preventDefault();
});

这是相当明确的，但转向（在所有浏览器的最新版本中）Firefox将使这个还可以使用箭头键和删除/退格键来防止移动，而其他浏览器则不会。

This is fairly strightforward, but turns that (in the latest version of all browsers) Firefox will make this also prevent movement with the arrow keys and delete/backspace keys, whereas the other browsers would not.

环顾四周我发现我还需要检查这些键，并检查 e 事件参考中公开的不同属性。

Looking around I found that I would need to also check for these keys, and check for different properties exposed in the e event reference.

我的最终代码如下所示：

My final code looks something like this:

$(textField).onKeyPress(function(e) {
    var code = e.which || e.keyCode;
    if (code > 31  // is not a control key
        && (code < 37 || code > 40) // is not an arrow key
        && (code < 48 || code > 57) // is not numeric
        && (code != 46) // is not the delete key
    )
        e.preventDefault();
});

然而，这对于解决一个相当简单的问题感觉太多了，因为只是防止非数字化。

However, this feels to be too much to solve a fairly simple problem as just preventing non-numeric.

我做错了什么？在这种验证方面哪个是最佳做法？

推荐答案

我们会回复两个按键，和模糊事件。当某人按下某个键时，我们会检查输入的密钥是否为数字。如果是，我们允许。否则，我们会阻止它。

We'll respond to both keypresses, and the blur event. When somebody press a key, we check to see if the key entered is a number. If it is, we permit it. Otherwise, we prevent it.

如果字段模糊，我们会删除所有非数字值以及后面的所有值。这将阻止用户粘贴非数字字符串：

If the field is blurred, we remove any non-numerical values, and all those values that follow. This will prevent the user from pasting in non-numerical strings:

$("#textfield").on("keypress blur", function(e){
    if ( e.type === "keypress" )
        return !!String.fromCharCode(e.which).match(/^\d$/);
    this.value = this.value.replace(/[^\d].+/, "");
});

演示： http://jsfiddle.net/jonathansampson/S7VhV/5/

这篇关于哪种方法可以过滤文本字段的数值？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！