在表单加载后添加href

Question

I have 3 dropdowns. Only when Australia is selected from the country dropdown, I have to show a help hyperlink for the city dropdown. The user can read some guidelines when he selects Australia before he can select a city. For this I want to append the 'City' label with an a href. How can I achieve this? I tried the following but failed:

function ddCountryChange() 
 {
     var ddCountry = document.getElementById("ddCountry");
     var tbCity = document.getElementById("tbCity ");
     if (ddCountry.value == "AUS"){               
            tbCity.innerHTML = '<div class="GXIRowTitle"><a href="/City-Search.ashx" target="_blank" style="color:blue">[<u>Help</u>]</a>&nbsp;<span style="font-weight:normal;">City : &nbsp;&nbsp;</span></div><div class="GXIRowControl"><div id="ctl02_ctl00_GXDivLeft_TbCity_TbBoxReadOnly" style="display: none;">&nbsp;</div><span id="ctl02_ctl00_GXDivLeft_TbCity_TbBoxNonReadOnly" style="display: inline;"><input name="ctl02$ctl00$GXDivLeft$TbCity$TbBox" type="text" maxlength="64" id="ctl02_ctl00_GXDivLeft_TbCity_TbBox" autocomplete="off"><ul id="ctl02_ctl00_AcCity_completionListElem" class="GXAutoComplete_CompletionListElement" style="position: absolute;"></ul></span><input type="image" name="ctl02$ctl00$GXDivLeft$TbCity$Btn" id="ctl02_ctl00_GXDivLeft_TbCity_Btn" align="ABSMIDDLE" src="/ucommand/CRM/images/icn/DropDown.gif" alt="Show List" onclick="javascript:onAutoCompleteViewList("ctl02_ctl00_AcCity");return false;" style="border-width:0px;"></div>';
        }
 }

While debugging through Firebug, I see that the city label is appended with a 'Help', but once the process finishes, the 'Help' disappears.

Answer 1

Assuming ddCountry is the select element

 // Detect when value is changed
ddCountry.addEventListener("change", function(e){

  // Is its value now "AUS"?
  if(this.value == "AUS"){
      // Do stuff such as appending whatever label
  }else{
      // Hide stuff again?
  }

});