Jquery：在按键上过滤输入 [英] Jquery: filter input on keypress

问题描述

我有一个文字字段，只接受以下字符：

I have a text field, which will accept only the following characters:

允许字符：[az 0-9 +＃ - 。]

当您提出问题时，这与标签字段中的 SO 过滤器相同。
如果用户键入无效字符，我希望当前文本字段值保持不变。我试过了：

This is the same filter SO does in the 'Tags' field, when you're asking a question. If the user types an invalid character, i want the current text field value to remain unchanged. I tried:

$('#post_tags').keypress(function(event){
    var char = String.fromCharCode(event.which)
    var txt = $(this).val()

    if (! txt.match(/[^A-Za-z0-9+#-\.]/)){
        $(this).val(txt.replace(char, ''));
    }
})

为什么它不起作用？谢谢！

Why it doesn't work? Thanks!

推荐答案

/[^A-Za-z0-9+#-\.]/

这会否定任何一个字符的匹配。要使其匹配多个字符，您必须在其中使用 + ：

This negates the match of any one of those characters. To make it match more than one character, you have to use a + in there:

/[^A-Za-z0-9+#-\.]+/
                  ^

现在要匹配整个字符串，你需要添加锚点：

And now to match the whole string, you need to add anchors:

/^[^A-Za-z0-9+#-\.]+$/
 ^                  ^

<编辑：好的，这里的 - 似乎也在创建一个从字符＃到<$ c的范围$ C> 。在这种情况下，您可以将其转义，或将其放在最后：

Okay, it seems that the - here is also creating a range from character # to .. In this case, you can either escape it, or put it at the end:

/^[^A-Za-z0-9+#\-\.]+$/

/^[^A-Za-z0-9+#\.-]+$/

这篇关于Jquery：在按键上过滤输入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！