如何防止用户在长度为0时在文本框中输入特殊字符？

I have the following code which prevents user from entering space when the length is 0. Now, how can I prevent user from entering all special characters(anything other than a-z A-Z 0-9) when the length is 0?

我有以下代码,当长度为0时,阻止用户输入空格。现在,当长度为0时,如何防止用户输入所有特殊字符(a-z A-Z 0-9以外的任何字符)?

$('#DivisionName').bind('keypress', function(e) {
    if($('#DivisionName').val().length == 0){
        if (e.which == 32){//space bar
            e.preventDefault();
        }
    }
});

This is my text box.

这是我的文本框。

<input type="text" id="DivisionName" />

3 个解决方案

#1

The letter and digit ranges are (inclusive):

字母和数字范围是(包括):

97 - 122 (a-z)

97 - 122(a-z)

65 - 90 (A-Z)

65 - 90(A-Z)

48 - 57 (0-9)

48 - 57(0-9)

This is what you compare e.which against.

这是你比较e.which反对。

if (e.which < 48 || 
    (e.which > 57 && e.which < 65) || 
    (e.which > 90 && e.which < 97) ||
    e.which > 122) {
    e.preventDefault();
}

Or, using inverse logic:

或者,使用逆逻辑:

var valid = (e.which >= 48 && e.which <= 57) || (e.which >= 65 && e.which <= 90) || (e.which >= 97 && e.which <= 122);
if (!valid) {
    e.preventDefault();
}

Update

Even so, you may still wish to validate the field contents as a whole using a regular expression:

即便如此,您仍可能希望使用正则表达式整体验证字段内容:

if (/^[A-Z0-9]+$/i.test(value)) {
    // it looks okay now
}

Or fix the field by replacing the bad stuff:

或者通过替换坏东西来修复该字段:

var stripped = value.replace(/[^A-Z0-9]+/i, '');

#2

This is what you are looking for:

这就是你要找的东西:

$('#DivisionName').bind('keypress', function(e) {

    if($('#DivisionName').val().length == 0){
        var k = e.which;
        var ok = k >= 65 && k <= 90 || // A-Z
            k >= 97 && k <= 122 || // a-z
            k >= 48 && k <= 57; // 0-9

        if (!ok){
            e.preventDefault();
        }
    }
});

or see here: http://jsfiddle.net/D4dcg/

或者看到这里:http://jsfiddle.net/D4dcg/

#3

-1

You can use a regex to validate the string. Something like ^[a-zA-z0-9].*

您可以使用正则表达式来验证字符串。像^ [a-zA-z0-9]这样的东西。*

Here is an article about testing a regex in javascript : http://www.w3schools.com/jsref/jsref_regexp_test.asp

这是一篇关于在javascript中测试正则表达式的文章:http://www.w3schools.com/jsref/jsref_regexp_test.asp

And you can even bind a change event and not a keypress.

您甚至可以绑定更改事件而不是按键。

#1