Question

我想在用户专注于select元素时触发事件。我无法编辑正文代码。所以我试图通过JS在头脑中实现它。如果我可以添加属性到我的选择元素甚至从标头标记中的Javascript。

我希望在用户点击select元素时显示警报。帮助

    <html>
    <head>
    <script>
    window.onload = function()
    {   

        var f = document.getElementById("CheckForm");

        var temp = document.getElementById("CheckForm.t1");
        if(f.name == "CheckForm")
        {
          var temp1 = document.getElementById("t1");
          temp1.value = "Task";
        }
        if(document.getElementByd("t2").focus)
        {
            alert("hello");
        }       

    }

   </script>
   </head>
   <body>
    <form name="CheckForm" id="CheckForm">
    t1: <input type="text" id="t1" name="t1"/>
    t2: <select id="t2">
        <option></option>
                    <option>1</option>
        <option>2</option>
        </select>   
    t3: <input type="text" id="t3" name="t3"/>
   </form>
 </body>
 </html>

Answer 1

试试这个：

document.getElementById("t2").setAttribute("onclick", "alert()");

Answer 2

尝试以下代码

    var att=document.createAttribute("onclick");
    att.value="yourFunction()";         
    document.getElementById("t2").setAttributeNode(att);


function yourFunction(){
// your js code
}

Answer 3

使用此功能，当选择框获得焦点时会出现警告消息

<html>
        <head>
        <script>
        window.onload = function()
        {   

            var f = document.getElementById("CheckForm");

            var temp = document.getElementById("CheckForm.t1");
            if(f.name == "CheckForm")
            {
              var temp1 = document.getElementById("t1");
              temp1.value = "Task";
            }
            if(document.getElementById("t2").focus)
            {
                alert("hello");
            }   

            document.getElementById("t2").setAttribute("onfocus", "selectHiglight()");

        }

    var selectHiglight=function(){
        alert('select get hilghited');
    };

       </script>
       </head>
       <body>
        <form name="CheckForm" id="CheckForm">
        t1: <input type="text" id="t1" name="t1"/>
        t2: <select id="t2">
            <option></option>
                        <option>1</option>
            <option>2</option>
            </select>   
        t3: <input type="text" id="t3" name="t3"/>
       </form>
     </body>
     </html>

通过Javascript动态设置焦点

3 个答案: