如何在asp.net的文本框占位符中使用mathjax？

<asp:TextBox ID="txtMath" runat="server" Placeholder="mathjax_placeholder"></asp:TextBox>

<script type="text/javascript">
    window.onload = function () {
        var textBox = document.getElementById('<%= txtMath.ClientID %>');
        var placeholder = textBox.getAttribute('placeholder');
        
        if (placeholder === 'mathjax_placeholder') {
            var mathText = textBox.value;
            var mathjaxContainer = document.createElement('div');
            mathjaxContainer.innerHTML = mathText;
            MathJax.Hub.Queue(["Typeset", MathJax.Hub, mathjaxContainer]);
            textBox.parentNode.insertBefore(mathjaxContainer, textBox);
            textBox.style.display = 'none';
        }
    };
</script>