Make a simple calculator in HTML using VBScript

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This is a very simple calculator made with HTML and coded with VBScript. This hta file simply evaluates the expression in the text box. The expression can be entered using the mouse to click the buttons or else from the keyboard. To prevent the chance of invalid data being entered, only numerical keys and the signs are allowed on the keyboard. Also you can use Enter key to evaluate the expression and C to clear the text box.

To make the calculator just save the following code with a .hta extension using notepad. Hope this code helps you improve your scripting!

Code:: <html>
<head>
<title>Calculator</title>
<HTA:APPLICATION
  APPLICATIONNAME="Calculator"
  ID="Calc"
  VERSION="1.0"
  SCROLL="no"
  MAXIMIZEBUTTON="no"
  SHOWINTASKBAR="no"/>
</head>

<style>

.btn{font-family: Arial;
  font-size: 12;
  color: #000000;
  background-color: #FFFFFF;
  width: 40;
  height: 25;}

.eq {font-family: Arial;
  font-size: 12;
  color: #000000;
  background-color: #FFFFFF;
  width: 40;
  height: 85;}

.0 {font-family: Arial;
  font-size: 12;
  color: #000000;
  background-color: #FFFFFF;
  width: 85;
  height: 25;}

</style>

<script language="VBScript">

Sub Window_OnLoad
   Dim width,height
   width=270
   height=300
   self.ResizeTo width,height
   box.focus
End Sub

Function btnb
On Error Resume Next
count = 0
text = box.value
count = Len(box.value)
count = count-1
box.value = Left(box.value, count)
End Function

Function eq
On Error Resume Next
junk = Eval(box.value)
If (Err.Number <> 0) Then
box.value = Err.Description
Else
box.value = Eval(box.value)
End If
End Function

Function AddBox(ID)
box.value = box.value&ID
End Function

Function KPS
If (window.event.keycode = 99) Then
box.value = ""
Else If (window.event.keycode = 13) Then
eq()
Else If (window.event.keycode = Then
btnb()
Else If ((window.event.keycode <> 94) And (window.event.keycode < 40 Or window.event.keycode > 41) And (window.event.keycode < 42 Or window.event.keycode > 57)) Then
window.event.returnvalue = False
Else
cxz.focus
box.value = box.value & Chr(window.event.keycode)
End If
End If
End If
End If
End Function

</script>

<body bgcolor="white" onkeypress="KPS">
<table align="center" id="cxz">
<caption><hr><b>CALCULATOR</b><hr></caption>
<tr>
<td colspan="5" align="center"><input type="text" id="box" size="30" onclick="cxz.focus" readonly>
</tr>
<tr>
<td colspan="2"><input type="button" value="Backspace" class="0" id="btna" onclick="btnb" onmouseover="btna.style.background = '#808080'" onmouseout="btna.style.background = '#FFFFFF'"></td>
<td><input type="button" value="(" class="btn" id="btnz" onclick="AddBox('(')" onmouseover="btnz.style.background = '#808080'" onmouseout="btnz.style.background = '#FFFFFF'"></td>
<td><input type="button" value=")" class="btn" id="btnc" onclick="AddBox(')')" onmouseover="btnc.style.background = '#808080'" onmouseout="btnc.style.background = '#FFFFFF'"></td>
<td><input type="button" value="C" class="btn" id="btnd" onclick="box.value = ''" onmouseover="btnd.style.background = '#808080'" onmouseout="btnd.style.background = '#FFFFFF'"></td>
</tr>
<tr>
<td><input type="button" value="7" class="btn" id="btne" onclick="AddBox('7')" onmouseover="btne.style.background = '#808080'" onmouseout="btne.style.background = '#FFFFFF'"></td>
<td><input type="button" value="8" class="btn" id="btnf" onclick="AddBox('8')" onmouseover="btnf.style.background = '#808080'" onmouseout="btnf.style.background = '#FFFFFF'"></td>
<td><input type="button" value="9" class="btn" id="btng" onclick="AddBox('9')" onmouseover="btng.style.background = '#808080'" onmouseout="btng.style.background = '#FFFFFF'"></td>
<td><input type="button" value="/" class="btn" id="btnh" onclick="AddBox('/')" onmouseover="btnh.style.background = '#808080'" onmouseout="btnh.style.background = '#FFFFFF'"></td>
<td><input type="button" value="^" class="btn" id="btni" onclick="AddBox('^')" onmouseover="btni.style.background = '#808080'" onmouseout="btni.style.background = '#FFFFFF'"></td>
</tr>
<tr>
<td><input type="button" value="4" class="btn" id="btnj" onclick="AddBox('4')" onmouseover="btnj.style.background = '#808080'" onmouseout="btnj.style.background = '#FFFFFF'"></td>
<td><input type="button" value="5" class="btn" id="btnk" onclick="AddBox('5')" onmouseover="btnk.style.background = '#808080'" onmouseout="btnk.style.background = '#FFFFFF'"></td>
<td><input type="button" value="6" class="btn" id="btnl" onclick="AddBox('6')" onmouseover="btnl.style.background = '#808080'" onmouseout="btnl.style.background = '#FFFFFF'"></td>
<td><input type="button" value="*" class="btn" id="btnm" onclick="AddBox('*')" onmouseover="btnm.style.background = '#808080'" onmouseout="btnm.style.background = '#FFFFFF'"></td>
<td rowspan="3"><input type="button" value="=" class="eq" id="btnn" onclick="eq" onmouseover="btnn.style.background = '#808080'" onmouseout="btnn.style.background = '#FFFFFF'"></td>
</tr>
<tr>
<td><input type="button" value="1" class="btn" id="btno" onclick="AddBox('1')" onmouseover="btno.style.background = '#808080'" onmouseout="btno.style.background = '#FFFFFF'"></td>
<td><input type="button" value="2" class="btn" id="btnp" onclick="AddBox('2')" onmouseover="btnp.style.background = '#808080'" onmouseout="btnp.style.background = '#FFFFFF'"></td>
<td><input type="button" value="3" class="btn" id="btnq" onclick="AddBox('3')" onmouseover="btnq.style.background = '#808080'" onmouseout="btnq.style.background = '#FFFFFF'"></td>
<td><input type="button" value="-" class="btn" id="btnr" onclick="AddBox('-')" onmouseover="btnr.style.background = '#808080'" onmouseout="btnr.style.background = '#FFFFFF'"></td>
</tr>
<tr>
<td colspan="2"><input type="button" value="0" class="0" id="btns" onclick="AddBox('0')" onmouseover="btns.style.background = '#808080'" onmouseout="btns.style.background = '#FFFFFF'"></td>
<td><input type="button" value="." class="btn" id="btnt" onclick="AddBox('.')" onmouseover="btnt.style.background = '#808080'" onmouseout="btnt.style.background = '#FFFFFF'"></td>
<td><input type="button" value="+" class="btn" id="btnu" onclick="AddBox('+')" onmouseover="btnu.style.background = '#808080'" onmouseout="btnu.style.background = '#FFFFFF'"></td>
</tr>
</table>
</body>
</html>