CodeBehind

Public Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then

        End If
    End Sub

    Protected Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
        Dim loanAmount As Double
        Dim interestRate As Double
        Dim loanTerm As Double

        Try
            lblResult.ForeColor = Drawing.Color.Black ' reset the font color

            loanAmount = Convert.ToDouble(txtLoanAmount.Text)
            interestRate = Convert.ToDouble(txtInterestRate.Text) / 100 ' Convert to decimal
            loanTerm = Convert.ToDouble(txtLoanTerm.Text) * 12 ' Convert years to months

        Catch ex As Exception
            lblResult.ForeColor = Drawing.Color.Red
            lblResult.Text = "Invalid values were entered"
            Exit Sub
        End Try

        If loanAmount <= 0 OrElse loanTerm <= 0 Then

            lblResult.Text = "Please enter positive values for loan amount and term."
            lblResult.ForeColor = Drawing.Color.Red
            Exit Sub
        End If

        Dim monthlyInterestRate As Double = interestRate / 12

        lblResult.Text = "It was clicked"

    End Sub
End Class