The operation of JS decimal number and the verification of digital type

1. Discard the fractional part, preserving the whole number of parts
Js:parseint (7/2)

2. Rounding up, with decimals on the integer part plus 1
Js:Math.ceil (7/2)

3, rounded. Js:Math.round (7/2)

4, rounding down
Js:Math.floor (7/2)

Attached: How to determine the type of numeric input (without quotation marks when used!) ）

"^\\d+$"//nonnegative integer (positive integer + 0)
"^[0-9]*[1-9][0-9]*$"//Positive integer

"^ ((-\\d+) | (0+)) $ "//non-positive integer (negative integer + 0)
"^-[0-9]*[1-9][0-9]*$"//Negative integer

"^-?\\d+$"//Integer

"^\\d+ (\\.\\d+)? $"//non-negative floating-point number (positive floating point + 0)

^ ([0-9]+\\]. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*)) $ "//positive floating-point number

"^ ((-\\d+ (\\.\\d+)?) | (0+ (\\.0+)?)) $ "//non-positive floating-point number (negative floating-point number + 0)

^ (-([0-9]+\\]. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*))) $ "//negative floating-point number

^ (-?\\d+) (\\.\\d+)? $ "//floating-point number

Example:

var r =/^[0-9]*[1-9][0-9]*$///Positive integer

R.test (str); Str for the character you want to judge to perform the return result true or False

The operation of JS decimal number and the verification of digital type