javascript - 强制下拉问题

Question

我有一个包含多个必填字段的表单，除了下拉列表之外，所有这些字段都有效。

我使用此代码来检查字段:

function formCheck(formobj){
    // Enter name of mandatory fields
    var fieldRequired = Array("name", "country", "email", "tel");
    // Enter field description to appear in the dialog box
    var fieldDescription = Array("Name", "Country", "Email", "Telephone");
    // dialog message
    var alertMsg = "Please complete the following fields:\n";

    var l_Msg = alertMsg.length;

    for (var i = 0; i < fieldRequired.length; i++){
        var obj = formobj.elements[fieldRequired[i]];
        if (obj){
            switch(obj.type){
            case "select-one":
                if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""){
                    alertMsg += " - " + fieldDescription[i] + "\n";
                }
                break;
            case "select-multiple":
                if (obj.selectedIndex == -1){
                    alertMsg += " - " + fieldDescription[i] + "\n";
                }
                break;
            case "text":
            case "textarea":
                if (obj.value == "" || obj.value == null){
                    alertMsg += " - " + fieldDescription[i] + "\n";
                }
                break;
            default:
            }
            if (obj.type == undefined){
                var blnchecked = false;
                for (var j = 0; j < obj.length; j++){
                    if (obj[j].checked){
                        blnchecked = true;
                    }
                }
                if (!blnchecked){
                    alertMsg += " - " + fieldDescription[i] + "\n";
                }
            }
        }
    }

    if (alertMsg.length == l_Msg){
        return true;
    }else{
        alert(alertMsg);
        return false;
    }
}

这是我用于下拉列表的代码:

<select name="country" id="country">
                        <option value="" disabled="disabled">Please select your country</option>
                        <option value="United Kingdom">United Kingdom</option>
                        <option value="United States">United States</option>
...

让用户选择一个国家/地区而不是让用户选择“请选择您的国家/地区”并且不返回任何内容，我缺少什么？

Answer 1

对于您的示例，此代码将始终结果为 true:

obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""

两者都将评估为 true。尝试将其更改为:

obj.selectedIndex == 0