JavaScript获取Select选中值的完整示例

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>www.jb51.net javascript获取select值</title>
</head>
<script>
  //javascript获取选中select值
  /*
    var obj = document.getElementById("testSelect"); //定位id
    var index = obj.selectedIndex; // 选中索引
    var text = obj.options[index].text; // 选中文本
    var value = obj.options[index].value; // 选中值
  */
  //jQuery获取选中select值
  /*
    $('#testSelect option:selected').text();//选中的文本
    $('#testSelect option:selected') .val();//选中的值
    $("#testSelect ").get(0).selectedIndex;//索引
  */
  window.onload=function() {
    var oBtn=document.getElementById("oBtn1");
    var oText=document.getElementById("oText1");
    var oSelect=document.getElementById("select1");
    var index=oSelect.selectedIndex ;
    oBtn.onclick=function() {
      alert(oSelect.options[index].text);
      if(oText.value==""){
        alert("请输入内容")
      }else{
        alert(oText.value+"----"+oSelect.options[oSelect.selectedIndex].text)
      }
    }
  }
</script>
<body>
<input id="oText1" type="text" value=""/>
<input id="oBtn1" type="button" value="按钮"/>
<select id="select1">
  <option value="1">广州</option>
  <option value="2">上海</option>
  <option value="3">北京</option>
</select>
</body>
</html>