显示日，月和年代替当前日，月和年

I have the following javascript code which displays current day, month and year in the dropdown. The code is as follows:

我有以下javascript代码,在下拉列表中显示当前日期,月份和年份。代码如下:

var monthtext=['January','February','March','April','May','June','July','August','September','October','November','December'];

function populatedropdown(dayfield, monthfield, yearfield) {
   var today=new Date()
   var dayfield=document.getElementById(dayfield)
   var monthfield=document.getElementById(monthfield)
   var yearfield=document.getElementById(yearfield)
   for (var i=0; i<31; i++) {
      dayfield.options[i]=new Option(i+1)
   }
   dayfield.options[today.getDate()]=new Option(today.getDate(), today.getDate(), true, true) //select today's day
   for (var m=0; m<12; m++) {
      monthfield.options[m]=new Option(monthtext[m], monthtext[m])
   }
   monthfield.options[today.getMonth()]=new Option(monthtext[today.getMonth()], monthtext[today.getMonth()], true, true) //select today's month
   var thisyear=today.getFullYear()
   for (var y = 0; y < 100; y++) {
       yearfield.options[y] = new Option(thisyear, thisyear)
       thisyear -= 1
   }
   yearfield.options[0]=new Option(today.getFullYear(), today.getFullYear(), true, true) //select today's year
}

<script type="text/javascript">
//populatedropdown(id_of_day_select, id_of_month_select, id_of_year_select)
window.onload=function(){
populatedropdown("daydropdown", "monthdropdown", "yeardropdown")
}
</script>



 <select id="daydropdown" name="D-DOB"></select>  
   <select id="monthdropdown" name="M-DOB"></select>
   <select id="yeardropdown" name="Y-DOB"></select>

I wish to display "Select Day", "Select Month" and "Select Year" as default values in place of current values like:

我希望将“选择日”,“选择月份”和“选择年份”显示为默认值来代替当前值,例如:

<option value="">Select Day</option>

Fiddle: https://jsfiddle.net/u2m243qf/1/

EDIT:

Resolved by myself:

由我自己解决:

I have restructured my code and arrived at a simpler solution. New Fiddle at: https://jsfiddle.net/u2m243qf/9/

我重新构建了我的代码并得出了一个更简单的解决方案。新小提琴:https://jsfiddle.net/u2m243qf/9/

1 个解决方案

#1

If I understood your request you want to display a default value in your options? If so, just do:

如果我理解了您的请求,您希望在选项中显示默认值?如果是这样,那就做:

<option value="x" selected="your-selected"> Select day </option>

You can also find a deeper discussion on the topic here: How can I set the default value for an HTML <select> element?

您还可以在此处找到有关该主题的更深入讨论:如何设置HTML

... and in JS it is:

......在JS中它是:

dayfield.value = "Select Day";

#1