How to use javascript in asp to restrict registered user names in English and numbers

In ASP website development, the registration function is an important part, and the standardized restrictions on user names are also a particularly important part. This article will focus on how to use JavaScript to limit registered user names to English and numbers.

Why are there restrictions on registered usernames in English and numbers?

In the registration function, in order to ensure system security, it is generally necessary to impose standardized restrictions on user names. Among them, the most basic standardization restriction scheme is to restrict character types. For example, only valid character types are limited to English and numbers. Specifically, the main reasons why it is necessary to restrict registered user names to English and numbers are as follows:

1. System security: only English and numbers are allowed to be entered, which can effectively prevent SQL injection and cross-site scripting. attack.
2. Standardization: Limiting valid character types to English and numbers can simplify user input errors, as well as the difficulty of subsequent database data filtering and querying, and improve the maintainability of the website.
3. Aesthetics: Limiting the character types of user names can avoid irregular characters such as garbled characters and symbols, making the website more beautiful.

How to use JavaScript to limit registered user names to English and numbers?

In ASP website development, JavaScript can be used to limit registered user names to English and numbers. The specific implementation steps are as follows:

Step 1: Add a text box control and a submit button to the ASP page:

<input type="text" id="txtUserName" /><br />
<input type="button" value="注册" onclick="checkUserName();" />

Step 2: Write JavaScript code to implement user name type restrictions:

<script type="text/javascript">
    function checkUserName() {
        var userName = document.getElementById("txtUserName").value;
        var pattern = /^[a-zA-Z0-9]+$/;
        if (userName.length <= 0) {
            alert("用户名不能为空！");
            return false;
        }
        else if (!pattern.test(userName)) {
            alert("用户名只允许输入英文和数字！");
            return false;
        }
        else {
            alert("恭喜您，注册成功！");
            return true;
        }
    }
</script>

Step 3: Add form submission function

<form method="post" action="submit.asp">
    <input type="text" id="txtUserName" /><br />
    <input type="button" value="注册" onclick="checkUserName();" />
</form>

The specific analysis is as follows:

First, we added a text box control and a "Register" button to the page. When the user clicks the "Register" button, we implement a checkUserName() function through JavaScript code to check whether the user name meets the specification. The specific implementation of the checkUserName() function is as follows:

1. Get the user name entered by the user.
2. Use the regular expression pattern matching function to determine whether the user name is empty or contains illegal characters other than English and numbers.
3. If the username meets the normative requirements, a prompt will pop up and jump to the submission page.
4. If the user name does not meet the normative requirements, an error message will pop up.

Finally, we specify the form submission method as "post" and submit the results to the "submit.asp" page for processing. In this way, the user name information passed through JavaScript can be obtained through POST in the ASP page, and operations such as storage and sending verification can be performed.

Summary:

This article details how to use JavaScript to restrict registered user names in English and numbers in ASP. By using regular expressions to implement function judgment, we can greatly improve the standardization and security of the website while avoiding problems such as input errors. Of course, more complex registration restriction rules also need to be improved and controlled through other technical means.

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