Turn: JS to take float type after the decimal point two-digit method

Source: Internet
Author: User

JS in the decimal point after the two-bit method is the most commonly used is the rounding function, before I introduced the JS rounding a common function, here just use, below we take a float type decimal point after two some methods summary http://www.jb51.net/article/45884.htm

Use JavaScript to take the float type decimal point two, example 22.127456 to take 22.13, how to do?

1. Discard the fractional part, preserving the whole number of parts

parseint (5/2)

2. Rounding up, with decimals on the integer part plus 1

Math.ceil (5/2)

3, rounded.

Math.Round (5/2)

4, rounding down

Math.floor (5/2)

Alternative approach

1. The stupidest Way

Copy CodeThe code is as follows: function get () {var s = 22.127456 + "";     var str = s.substring (0,s.indexof (".") + 3); alert (str); }

2. Regular expression effect is good

Copy CodeThe code is as follows: <script type= "Text/javascript" > onload = function () {var a = "23.456322";     var anew; var re =/([0-9]+.[     0-9]{2}) [0-9]*/;     anew = A.replace (Re, "$"); alert (anew); } </script>

3. He is more clever ...

Copy CodeThe code is as follows:<script> var num=22.127456; Alert (Math.Round (num*100)/100); </script>

4. Friends who will use new things .... But we need ie5.5+ to support it.

5.js Reserved 2 decimal places (mandatory)

For the number of decimal places greater than 2 bits, with the above function is not a problem, but if less than 2 bits, such as: Changetwodecimal (3.1), will return 3.1, if you must need 3.10 such a format, then you need the following function:

Copy CodeThe code is as follows: function Changetwodecimal_f (x) {var f_x = parsefloat (x);         if (IsNaN (f_x)) {alert (' function:changetwodecimal->parameter error ');     return false;     } var f_x = Math.Round (x * 100)/100;     var s_x = f_x.tostring ();     var pos_decimal = S_x.indexof ('. ');         if (Pos_decimal < 0) {pos_decimal = S_x.length;     S_x + = '. ';     } while (S_x.length <= Pos_decimal + 2) {s_x + = ' 0 '; } return s_x; }

Function: Rounding the floating-point number, take 2 digits after the decimal point, if less than 2 bit 0, this function returns the format usage of the string: Changetwodecimal (3.1415926) return 3.14 changetwodecimal (3.1) return 3.10

Turn: JS to take float type after the decimal point two-digit method

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