How to set the value of a text box with javascript on an ASP.NET webform

Question

so in a form I have the following control:

<asp:TextBox runat="server" ID="monthlyAmount" ClientIDMode="Static"/>

The ClientIDMode Static is because a master page is in use.

I then have this Button:

<input type="button" id="calculate" onclick="AutoFillEstimate()" value="Calculate Estimate" />

Wired to this Script:

<script type="text/javascript">
    function AutoFillEstimate() {
        document.getElementById("monthlyAmount").nodeValue = "test";
    }
</script>

I feel like I'm just using nodeValue instead of what I should be using, but I have no idea where to look for reference on these things.

Answer 1

如果我理解正确，你只是想设置值，只需使用：

document.getElementById("monthlyAmount").value = "test";

Answer 2

正确的方法是：

document.getElementById("<%= monthlyAmount.ClientID %>").value = "test";