[JavaScript] 通用数值格式化

1、将正数转化为美元数值

<html>

<head>

<title>Number Formatting</title>

<!--

// generic positive number decimal formatting function

function format(expr, decplaces) {

// raise incoming value by power of 10 times the

// number of decimal places; round to an integer; convert to string

var str = "" + Math.round(eval(expr) * Math.pow(10,decplaces));

// pad small value strings with zeros to the left of rounded number

while (str.length <= decplaces) {

str = "0" + str;

}

// establish location of decimal point

var decpoint = str.length - decplaces;

// assemble final result from: (a) the string up to the position of

// the decimal point; (b) the decimal point; and (c) the balance

// of the string. Return finished product.

return str.substring(0,decpoint) + "." +

str.substring(decpoint,str.length);

}

// turn incoming expression into a dollar value

function dollarize(expr) {

return "$" + format(expr,2);

}

//-->

</script>

</head>

<body>

<h1>How to Make Money</h1>

<form>

Enter a positive floating point value or arithmetic expression to be

converted to a currency format:

<input type="button" value=">Dollars and Cents>" onclick="this.form.result.value=dollarize(this.form.entry.value)" />

</form>

</body>

</html>

2、将10进制转化成16进制

function toHex(dec) {

hexChars = "0123456789ABCDEF";

if (dec > 255) {

return null;

}

var i = dec % 16;

var j = (dec - i) / 16;

result = "0X";

result += hexChars.charAt(j);

result += hexChars.charAt(i);

return result;

}