Javascript运行时错误:无法获取property 'style'动态创建的文本框的未定义引用或空

本文关键字：文本 运行时错误 未定义 引用 创建 动态 property 获取 style Javascript | 更新日期: 2023-09-27 18:13:41

我在ASP.NET C# Code-Behind中创建了一些文本框，并试图使用简单的javascript来样式它们，我也想从Code-Behind调用。

问题是，我得到一个Javascript运行时错误。错误是"0x800a138f - JavaScript runtime error: Unable to get property 'style' of undefined or null reference"

我的"。Aspx "页面如下:

<head runat="server">
  <title></title>
  <script type="text/javascript">
    function call_me(x) {
      var txtbox = document.getElementById(x);
      txtbox.style.backgroundColor = 'black';
      txtbox.style.color = 'yellow';
    }
  </script>
</head> 
<body>
  <form id="form1" runat="server">
    <div>
      <asp:Panel ID="Panel1" runat="server"></asp:Panel>
    </div>
  </form>
</body>

我的"c# Code-Behind"文件如下:

protected void Page_Load(object sender, EventArgs e) {
  for (int i = 0; i < 5; i++) {
    //textbox creation
    TextBox tx = new TextBox();
    tx.ID = "textbox" + i.ToString();
    string client_id = tx.ClientID;
    tx.Text = client_id;
    //script and key creation
    string key_for_javascript = "call" + i.ToString();
    string script_to_load = "call_me('" + client_id + "');";
    //add textbox to panel
    Panel1.Controls.Add(tx);
    //call script
    ScriptManager.RegisterClientScriptBlock(this, this.GetType(), key_for_javascript, script_to_load, true);
  }
}

我不确定我在哪里出错或我应该如何解决这个问题。请帮帮我!

Javascript运行时错误:无法获取property 'style'动态创建的文本框的未定义引用或空

可以试试下面的代码吗

 for (int i = 0; i < 5; i++)
        {
            //textbox creation
            TextBox tx = new TextBox();
            tx.ID = "textbox" + i.ToString();
            string client_id = tx.ClientID;
            tx.Text = client_id;
            //script and key creation
            string key_for_javascript = "call" + i.ToString();
            string script_to_load = "call_me('" + client_id + "');";
            //add textbox to panel
            Panel1.Controls.Add(tx);
            //call script
         //   ScriptManager.RegisterClientScriptBlock(this, this.GetType(), key_for_javascript, script_to_load, true);
            Page.ClientScript.RegisterStartupScript(GetType(), key_for_javascript, script_to_load, true);
        }
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