我在JavaScript 學習如何基於 var typeSelectBox = "<select id='depprojsDevice' class='selectpicker'>";
typeSelectBox += "<option value=''> -- SELECT --</option>";
if (arr) {
for (var i in arr) {
ty
如何使選擇表單爲必填項?我嘗試了「需要」,但它不起作用。 <div class="form-group">
<label for="sel2">How many years have you been trading *</label>
<select class="form-control" id="sel2" required>
<option>Please s