How does javascript detect decimals

This article mainly introduces javascript how to detect decimals, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Javascript decimal detection method: 1, the use of indexOf (), syntax "String (num) .indexOf (". ")", if the return value is greater than "- 1" is a decimal. 2. Using regular expressions, the syntax "var rep=/ [\.] /; rep.test (num)".

The operating environment of this tutorial: windows7 system, javascript1.8.5 version, Dell G3 computer.

Javascript method to detect whether it is a decimal or not

Method 1: using indexOf () method

Train of thought:

Decimals have decimal points. We can use the indexOf () method to determine the location of the decimal point to determine whether it is a decimal, and if the return value of the indexOf () method is more than-1, it is a decimal.

Implementation code:

Function isDot (num) {if (String (num) .indexOf (".") >-1) {console.log ("is a decimal");} else {console.log ("not a decimal");} isDot (121.121); / / isDot (454654) with decimal point; / / without decimal point

Output result:

Is a decimal, not a decimal.

Method 2: use regular expressions to determine whether it is a decimal or not

Function isDot (num) {var rep=/ [\.] /; if (rep.test (num)) {console.log ("is a decimal");} else {console.log ("not a decimal");}} isDot (121.121); / is a decimal isDot (454.654); / / is a decimal isDot (454654); / / is not a decimal

Output result:

Is a decimal is a decimal, not a decimal. Thank you for reading this article carefully. I hope the article "how to detect decimals in javascript" shared by the editor will be helpful to everyone. At the same time, I also hope that you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!