JavaScript DHTML/Data Type/Number

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Add different type variables together

  

<html>
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
var num1 = 1;
var num2 = 2;
var num3 = 3;
var fourthvar = "4";
var name1 = "a";
var name2 = "b";
alert(num1 + num2);
alert(num3 + fourthvar);
alert(name1 + name2);
</script>
</body>
</html>



Calculate circle area/Peri/Calculate sphere volume

   
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
function calcArea(){
    inpRadius = 3;
    alert(Math.PI * ((inpRadius)*(inpRadius)));
}
function calcPeri()
{
    inpRadius = 3;
    alert(2 * Math.PI * (inpRadius));
}
function calcVol()
{
    inpRadius = 3;
    alert(Math.PI * ((inpRadius)*(inpRadius)*(inpRadius)) * (4/3));
}
</script>
</head>
<body>
<input type="button" value="Calculate circle area" onclick="calcArea();"> 
<input type="button" value="Calculate circle Peri" onclick="calcPeri();">
<input type="button" value="Calculate sphere volume" onclick="calcVol();">
</body>
</html>



Calculate the average for integers

   
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
function calcAvg(){
    var inpNum1 = 1;
    var inpNum2 = 2;
    var inpNum3 = 3;
    var inpNum4 = 4;
    numAvg = doCalcAvg(inpNum1, inpNum2, inpNum3, inpNum4);
    alert("The average is: " + numAvg);
}
function doCalcAvg(inpNum1, inpNum2, inpNum3, inpNum4)
{
    var ans;
    ans = (Number(inpNum1) + Number(inpNum2) + Number(inpNum3) + Number(inpNum4)) / 4;
    return (ans);
}
</script>
</head>
<body onLoad="calcAvg();">
</body>
</html>



Check if it is a number and calculate the cubic power

  
<html>
<head>
<script type = "text/javascript">
function cubeme(aNum) {
    if (aNum == 1) {
        return 1;
    } else {
        return Math.pow(aNum,3);
    }
}
</script>
</head>
<body>
<script type = "text/javascript">
var theNum = 2;
var finalNum = cubeme(theNum);
if (isNaN(finalNum)) {
    alert("Not a number.");
} else {
    alert(finalNum);
}
</script>
</body>
</html>



Compare the value for integer numbers

   
<HTML>
<BODY>
<SCRIPT language="JavaScript">
var num1 = 0;
var num2 = 0;
if(num1 == num2) {
 window.alert("True");
}
else {
 window.alert("False");
}
</SCRIPT>
</BODY>
</HTML>



Convert a Number to a Exponential format

   
    
<html>
<body>
<button onclick="var myNum = new Number(100); alert(myNum.toExponential(1));">
Number toExponential
</button>
</body>
</html>



Convert a number to a precision

   
    
<html>
<body>
<button onclick="var myNum = new Number(100); alert(myNum.toPrecision(1));">
Number toPrecision
</button>
</body>
</html>



Convert a number to string by append empty string to it

   


<html>
<head>
</head>
<body>
<script type="text/javascript">
  function numToString(number) {
    number += "";
    return number;
  }
  var number = 100;
  alert(typeof number);
  number = numToString(number);
  alert(typeof number);
</script>
</body>
</html>



Convert Fahrenheit to Celsius

   
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
function inputFah(){
    var fah = 100;
    ansCel = doCelCalc(fah);
    alert(fah + " Degrees Fahrenheit is " + ansCel + " Degrees Celsius");
}
function doCelCalc(fah){
    var ans = ((Number(fah) - 32) / 1.8);
    return (ans);
}
</script>
</head>
<body>
    <input type="button" value="Convert Fahrenheit to Celsius" onClick="inputFah();">
</body>
</html>



Convert from Celsius to Fahrenheit

   
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
function inputCels(){
    var cels = 100;
    ansFah = doFahCalc(cels);
    alert(cels + " Degrees Celsius is " + ansFah + " Degrees Fahrenheit");
}
function doFahCalc(cels){
    var ans = ((1.8 * Number(cels)) + 32);
    return (ans);
}
</script>
</head>
<body>
<input type="button" value="Convert Celsius to Fahrenheit" onClick="inputCels();">
</body>
</html>



Declare float point number, boolean value and null value

   
<HTML>
<BODY>
<SCRIPT language="JavaScript">
<!--
    var c=2.59;
    var i=false;
    var n=null;
    document.write("\"This is fun!\"");
//-->
</SCRIPT>
</BODY>
</HTML>



Fix a number

   
    
<html>
<body>
<button onclick="var myNum = new Number(100.22); alert(myNum.toFixed(1));">
Number toFixed
</button>
</body>
</html>



Hexadecimal Numbers

  
<html>
<head>
<script type = "text/javascript">
var h = 0xe;
var i = 0x2;
var j = h * i;
document.write(j);
</script>
</head>
</html>



Integer math calculation

   
<HTML>
<BODY>
<SCRIPT language="JavaScript">
var intValue=200;
document.write(intValue+"<BR>");
intValue += 200;
document.write(intValue+"<BR>");
intValue = intValue-50;
document.write(intValue+"<BR>");
intValue = intValue*0;
document.write(intValue+"<BR>");
intValue = intValue + 500;
document.write(intValue+"<BR>");
intValue -= 80;
document.write(intValue+"<BR>");
</SCRIPT>
</BODY>
</HTML>



Read a number and compare its value

  
<html>
<head>
    <title>An If Example</title>
</head>
<body>
<script type = "text/javascript" >
var inputNum = prompt("Please enter a number below 100:");
if (inputNum > 99) {
    document.write("That number, " + inputNum + ", is not below 100.");
}
</script>
</body>
</html>



Using Binary Flags

   
<html>
<head>
<title>Using Binary Flags</title>
<script type="text/javascript">
var FIELD_A = 0x1;  // 00001
var FIELD_B = 0x2;  // 00010
var FIELD_C = 0x4;  // 00100
var FIELD_D = 0x8;  // 01000
var FIELD_E = 0x10; // 10000
var fieldsSet = FIELD_A | FIELD_C | FIELD_E;
if ((fieldsSet & FIELD_A) && (fieldsSet & FIELD_C)) {
   document.write("Fields A and C are set");
}
</script>
</head>
</body>
</html>
Источник — «http://wbex.ru/index.php?title=JavaScript_DHTML/Data_Type/Number&oldid=1755»