check if value in drop down list match value entered in textbox

<input type="text" id="txtLoginType"/>
  <select id="ddlloginType" onchange="return validate();">
    <option>Select</option>
    <option>lecturer</option>
    <option>student</option>
  </select>

function validate()
{
var content = document.getElementById('txtLoginType');
  var dropdownType = document.getElementById('ddlloginType');
if (content.value == dropdownType.options[dropdownType.selectedIndex].value)
  {
  alert('Valid');
    //Doo your valid function
  }
  else
  {
    alert('Invalid');
    //Doo your Invalid function
  }
}