Allow only numbers and dot in script

The Solution to Allow only numbers and dot in script is


This is a great place to use regular expressions.

By using a regular expression, you can replace all that code with just one line.

You can use the following regex to validate your requirements:

[0-9]*\.?[0-9]*

In other words: zero or more numeric characters, followed by zero or one period(s), followed by zero or more numeric characters.

You can replace your code with this:

function validate(s) {
    var rgx = /^[0-9]*\.?[0-9]*$/;
    return s.match(rgx);
}

That code can replace your entire function!

Note that you have to escape the period with a backslash (otherwise it stands for 'any character').

For more reading on using regular expressions with javascript, check this out:

You can also test the above regex here:


Explanation of the regex used above:

  • The brackets mean "any character inside these brackets." You can use a hyphen (like above) to indicate a range of chars.

  • The * means "zero or more of the previous expression."

  • [0-9]* means "zero or more numbers"

  • The backslash is used as an escape character for the period, because period usually stands for "any character."

  • The ? means "zero or one of the previous character."

  • The ^ represents the beginning of a string.

  • The $ represents the end of a string.

  • Starting the regex with ^ and ending it with $ ensures that the entire string adheres to the regex pattern.

Hope this helps!

~ Answered on 2012-03-21 06:23:18


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