好，在堆叠器的帮助下，我能够得到一条错误消息，显示在输入表单下面。

我需要的是当用户在表单中输入任何输入时不显示错误消息。我做错了什么？

以下是HTML

<form id="url">
        <input type="text" name="urlName">
        <input type="submit" value="Build Your App"></input>
    </form>
    <div id="error-message">

    </div>

这是JS

document.getElementById("url").addEventListener("submit", (event) => {
            event.preventDefault()
            let errorMessage = document.getElementById("error-message").innerHTML = "Please provide your store URL";
            let myForm = document.getElementById("url");
            let formData = new FormData(myForm);
            if (formData.get("urlName") === "")
            return errorMessage;
            EndOfUrl = sanitizeDomainInput(formData.get("urlName"));
            newUrl = redirectLink(EndOfUrl);
            window.location.href = newUrl;
            return false;
        });


    function sanitizeDomainInput(input) {
        input = input || 'unknown.com'
        if (input.startsWith('http://')) {
            input = input.substr(7)
        }
        if (input.startsWith('https://')) {
            input = input.substr(8)
        }
            var regexp = new RegExp(/^(([a-zA-Z]{1})|([a-zA-Z]{1}[a-zA-Z]{1})|([a-zA-Z]{1}[0-9]{1})|([0-9]{1}[a-zA-Z]{1})|([a-zA-Z0-9][a-zA-Z0-9-_]{1,61}[a-zA-Z0-9]))\.([a-zA-Z]{2,6}|[a-zA-Z0-9-]{2,30}\.[a-zA-Z]{2,3})$/)
            return regexp.test(input) ? input : 'unknown.com';

            
    }

    function redirectLink(domain) {
        return `https://dashboard.getorda.com/signup/?state=${domain}`;
    }

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顺晟科技：

会有flash的报错，虽然说跳，我也不知道为什么，和楼主一起等答案

无论在任何情况下是否有导致消息出现的错误，都将错误消息分配给错误消息容器div。 请参考下面的代码片段，在这里我将错误消息分配移到了错误条件中。

document.getElementById("url").addEventListener("submit", (event) => { event.preventDefault() let errorMessage = "Please provide your store URL"; let myForm = document.getElementById("url"); let formData = new FormData(myForm); if (formData.get("urlName") === "") { document.getElementById("error-message").innerHTML = errorMessage; } EndOfUrl = sanitizeDomainInput(formData.get("urlName")); newUrl = redirectLink(EndOfUrl); window.location.href = newUrl; return false; }); function sanitizeDomainInput(input) { input = input || 'unknown.com' if (input.startsWith('http://')) { input = input.substr(7) } if (input.startsWith('https://')) { input = input.substr(8) } var regexp = new RegExp(/^(([a-zA-Z]{1})|([a-zA-Z]{1}[a-zA-Z]{1})|([a-zA-Z]{1}[0-9]{1})|([0-9]{1}[a-zA-Z]{1})|([a-zA-Z0-9][a-zA-Z0-9-_]{1,61}[a-zA-Z0-9]))\.([a-zA-Z]{2,6}|[a-zA-Z0-9-]{2,30}\.[a-zA-Z]{2,3})$/) return regexp.test(input) ? input : 'unknown.com'; } function redirectLink(domain) { return `https://dashboard.getorda.com/signup/?state=${domain}`; } <form id="url"> <input type="text" name="urlName"> <input type="submit" value="Build Your App"></input> </form> <div id="error-message"> </div>