javascript - 获取div中select的值

Question

我试图让 SELECT 放弃它从这个 HTML 中获得的值，这是强加给我的。

从控制台来看，我似乎到达了页面上的正确位置，但是当尝试检查我是否在那里时，if = SELECT 没有返回正确的内容...

谁能帮忙...

感谢和问候

<div id="Select1" class="dingbats_form_entry">
    <div class="dingbats_form_vertical_panel">
        <div>
            <div class="dingbats_form_label dingbats_form_label_top">Select1 </div>
            <div class="dingbats_form_field list_container" style="width: 100px;">
                <select class="gwt-ListBox dingbats_form_field_bottom" style="width: 135px;">
                    <option value="1">1</option>
                    <option value="2">2</option>
                    <option value="3">3</option>
                    <option value="4">4</option>
                    <option value="5">5</option>
                </select>
            </div>
        </div>
    </div>
</div>

我的代码为

<script>
function isRealValue(obj) {
    return obj && obj !== "null" && obj !== "undefined";
}

function getValue(ddl) {

    try {
        var obj = document.getElementById(ddl);
        if (isRealValue(obj)) {
            var lvl1 = obj.children;
            console.log(lvl1);
            var lvl2 = lvl1[0].children;
            console.log(lvl2);
            var lvl3 = lvl2[0].children;
            console.log(lvl3);
            var lvl4 = lvl3[1].children;
            console.log(lvl4);
            if (lvl4.tagName == 'SELECT') {
                alert("FOUND IT!!");
            }
            try {
                var val = obj.options[obj.selectedIndex].value;
            } catch (err) {
                window.alert("var val = obj.options[obj.selectedIndex].value " + err.message);
            }
            window.alert("myFunction: after Sel val:  Indx" + ddl + " " + val);
            document.getElementById("demo").innerHTML = val;
        } else {
            window.alert("obj is not a real object: " + ddl + " " + obj);
        }
    } catch (err) {
        window.alert("var obj = document.getElementById(ddl)  " + err.message);
    }
}

if (document.getElementById("Select1")) {
    document.getElementById("Select1").addEventListener("change", function () {
        getValue("Select1");
    });
} else {
    window.alert("Select1 not found");
}
</script>

Answer 1

你离我们并不遥远。使用 getElementsByTagName() 来简化它并在每个阶段添加检查以避免不必要的 try/catch。下面的代码未经测试。

function getValue(ddl) {
    var el = document.getElementById(ddl);
    if (el) {
        var selects = el.getElementsByTagName("select");
        if (selects.length > 0) {
            return selects[0];
            if (select.selectedIndex >= 0) {
                return select.value;
            }
        }
    }
    return null;
}