كيفي عمل آلة حاسبة

<HTML>
<HEAD>
<TITLE>A Simple Calculator in JavaScript</TITLE>

<script type="text/javascript">
<!--
function opr()
{

var firstNumber=document.all['First_Number'].value;
var secondNumber=document.all['Second_Number'].value;
var operator=document.all['operator_list'].value;
var result;
	if(firstNumber=="" || secondNumber==""){
			alert("the number isn't valid!!");
	}else {
		switch(operator){
			case 'add': result= firstNumber + secondNumber; break;
			case 'subtract': result= firstNumber - secondNumber; break;
			case 'multiply': result= firstNumber * secondNumber; break;
			case 'square': {
				result=  Math.sqrt(firstNumber);
				result+= "  :  ";
				result+=  Math.sqrt(secondNumber);
				break;
			}
			case 'divide': {
				if(secondNumber==0){
					result = "Arithmetic Exception : / by zero"
				}else{
					result= firstNumber / secondNumber; break;
				}
			}
		}
		alert(result);
	}

}

// OnlyNumbers
function checkIt(evt) {
	evt = (evt) ? evt : window.event
	var charCode = (evt.which) ? evt.which : evt.keyCode
	if (charCode > 31 && (charCode < 48 || charCode > 57))return false;
	return true;
}

-->
</script>

</HEAD>
<BODY BGCOLOR=lightblue>
<FORM NAME=calculator>
<TABLE BORDER=3 ALIGN = CENTER WIDTH=22%>
<caption><H1>My Calculator</H1></caption>
<TR ALIGN=CENTER><TD COLSPAN=2><h3>Please Enter two numbers below:</h3></TD></TR>
<TR ALIGN=CENTER><TD>
<INPUT TYPE=TEXT SIZE=8 NAME=First_Number onkeypress="return checkIt(event);">
</TD><TD>
<INPUT TYPE=TEXT SIZE=8 NAME=Second_Number	onkeypress="return checkIt(event);"></TD></TR>
<TR ALIGN=CENTER>
<TD><SELECT NAME=operator_list>
  <OPTION VALUE="add">+
  <OPTION VALUE="subtract">-
  <OPTION VALUE="divide" SELECTED>/
  <OPTION VALUE="multiply">*
  <OPTION VALUE="square">sqr
	</SELECT></TD>
<TD><INPUT TYPE=BUTTON NAME=calculate_button VALUE=Calculate onClick="opr()"></TD>
</TR>
<TR ALIGN=CENTER><TD COLSPAN=2><INPUT TYPE=Reset NAME=reset_button VALUE=Reset></TD>
</TR>
</TABLE>
</FORM>
</BODY>
</HTML>

كيفي عمل آلة حاسبة

مواضيع مشابهة