Microsoft® JScript™ parseInt Method

Language Reference  Version 1

See Also                  Applies To

Description

Converts strings into integers.

Syntax

parseInt(numstring, [radix])

The parseInt method syntax has these parts:

Part	Description
numstring	Required. A string to convert into a number.
radix	Optional. A value between 2 and 36 indicating the base of the number contained in numstring. If not supplied, strings with a prefix of '0x' are considered hexidecimal and strings with a prefix of '0' are considered octal. All other strings are considered decimal.

Remarks

The parseInt method returns an integer value equal to the number contained in numstring. If no prefix of numstring can be successfully parsed into an integer, NaN (not a number) is returned.

parseInt("abc")    // Returns NaN.
parseInt("12abc")  // Returns 12.

You can test for NaN using the isNaN method.

The uniary minus and plus operators will also convert a string to a number. E.g. var a = + "123" results in a numeric 123 in a.

  <SCRIPT>
  <!--
  var a = "123";
  var b = +a;
  document.write("<PRE>");
  document.write("<BR>a is "+a+" and is a "+typeof(a));
  document.write("<BR>b is "+b+" and is a "+typeof(b));
  document.write("</PRE>");
  // --> </SCRIPT>

You can also just use the "+" operator:

+'9.11'          // returns 9.11
+'-4'            // returns -4
+'0xFF'          // returns 255
+true            // returns 1
+'123e-5'        // returns 0.00123
+false           // returns 0
+null            // returns 0
+'Infinity'      // returns Infinity
+'1,234'         // returns NaN
+dateObject      // returns 1542975502981 (timestamp)
+momentObject    // returns 1542975502981 (timestamp)

However, be aware that + become concatinate as soon as anything preceeds it. e.g. 9 + "1" is "91" not 10. However, 9 - "1" is 8 because -'s other function is negate. So if you like you can do 9- -"1" and get 10. But not 9 --"1" because -- is decrement. Best just use parseInt or parseFloat