将Dropdown字段设为jsp中的强制字段

Question

I have a dropdown field that needs to be set as mandatory. The dropdown has the following source code

  <div id="dep-parent-dropdown" class="<%= depParDropdown %>">
    <%=provSelLabel %>
        <select name="province" id="province" onchange="javascript:get_cities('<%= currentNode.getPath() %>');">

    <%if(provinceVal==null || provinceVal.isEmpty()){ %>
         <option value=""><%=selOptionLabel %></option>
    <%}
    else { %>
        <option class="province_sel" value="<%= selectedProvince.getPath() %>"><%= selectedProvince.getName() %></option>
    <%}

    NodeIterator provincesNodeIter = provincesRootNode.getNodes();
    while(provincesNodeIter.hasNext()){
          Node provinceNode = provincesNodeIter.nextNode();

        %>
         <option value="<%= provinceNode.getPath() %>"><%= provinceNode.getName() %></option><%

     } 

    %>
    </select>
 </div>

I have tried the following but nothing seems to work.

Added required field to both parent and child dropdown like the below.

<div id="dep-parent-dropdown" class="<%= depParDropdown %>">
        <%=provSelLabel %>
        <select name="province" id="province" onchange="javascript:get_cities('<%= currentNode.getPath() %>');" required/>

Anyhelp would be much appreciated.

Answer 1

    Just keep your code in form tag and give "required" attribute to select 
    `<form>
    <div>
    <select required name="abc">
<option>Demo</option>
    </select>
    <input type="submit"/>
    </div> </form>`
    Hope it will help you

Answer 2

You have to add one default tag, for example:-

<select name="demo">
    <option value="NA">--Select--</option>
    //and here is your option tag
</select>

and apply JavaScript for tag, for example:-

if (document.forms[0].demo.value == "NA") {
    document.forms[0].demo.focus();
    result = false;
    break;
}

Answer 3

your code like this..

    <form action="" name="myform" id="myform">


    <div id="dep-parent-dropdown" class="<%= depParDropdown %>">
        <%=provSelLabel %>
            <select name="province" id="province" onchange="javascript:get_cities('<%= currentNode.getPath() %>');">
 **<option value="NA">--Select--</option>**

        <%if(provinceVal==null || provinceVal.isEmpty()){ %>
             <option value=""><%=selOptionLabel %></option>
        <%}
        else { %>
            <option class="province_sel" value="<%= selectedProvince.getPath() %>"><%= selectedProvince.getName() %></option>
        <%}

        NodeIterator provincesNodeIter = provincesRootNode.getNodes();
        while(provincesNodeIter.hasNext()){
              Node provinceNode = provincesNodeIter.nextNode();

            %>
             <option value="<%= provinceNode.getPath() %>"><%= provinceNode.getName() %></option><%

         } 

        %>
        </select>
     </div>

    <input type="button" name="btnSubmit" value="Register" id="button"  onclick="return validator();" />

    </form>

and your validator() javascript method like this:-

   function validator() {
    var result=true;
    if (document.forms[0].province.value == "NA") {
        document.forms[0].province.focus();
        result = false;
breack;
    }
    else if (result) {
            document.getElementById("myform").submit();
        }
    }

hope, this will help you