javascript - 编写此 javascript 的更有效方法

Question

我正在为我的网站创建一个联系表单，并在提交之前使用 javascript 进行第一层验证，然后通过 php 再次检查，但我对 javascript 比较陌生，这是我的脚本...

$("#send").click(function() {
    var fullname = $("input#fullname").val();
    var email = $("input#email").val();
    var subject = $("input#subject").val();
    var message = $("textarea#message").val();
    if (fullname == ""){
        $("input#fullname").css("background","#d02624");
        $("input#fullname").css("color","#121212");
    }else{
        $("input#fullname").css("background","#121212");
        $("input#fullname").css("color","#5c5c5c");
    }
    if (email == ""){
        $("input#email").css("background","#d02624");
        $("input#email").css("color","#121212");
    }else{
        $("input#email").css("background","#121212");
        $("input#email").css("color","#5c5c5c");
    }
    if (subject == ""){
        $("input#subject").css("background","#d02624");
        $("input#subject").css("color","#121212");
    }else{
        $("input#subject").css("background","#121212");
        $("input#subject").css("color","#5c5c5c");
    }
    if (message == ""){
        $("textarea#message").css("background","#d02624");
        $("textarea#message").css("color","#121212");
    }else{
        $("textarea#message").css("background","#121212");
        $("textarea#message").css("color","#5c5c5c");
    }
    if (name && email && subject && message != ""){
        alert("YAY");
    }
});

如果所有字段都已填写，我如何才能更有效地编写此代码并显示警报，谢谢。

Answer 1

$("#send").click(function() {
    var failed = false;

    $('input#fullname, input#email, input#subject, textarea#message').each(function() {
        var item = $(this);
        if (item.val()) {
            item.css("background","#121212").css("color","#5c5c5c");
        } else {
            item.css("background","#d02624").css("color","#121212");
            failed = true;
        }
    });

    if (failed){
        alert("YAY");
    }
});