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Regular Expression Allowing Input For Only Numbers and One Decimal

I want an input text box that restricts users to only enter numbers and one decimal point.

The regular expression I am using currently is /[^d.]/g.

Currently this allows the user to only input numbers and decimals but also allows for more than one decimal number. I am using it for a text box to allow only a string of numbers along with one decimal following another string of numbers but ends.

Text box code: onkeyup= "this.value=this.value.replace(/[^d.]/g, '' )".
Full html block: Enter your second number <input type="text" id="num2" onClick="(this.value='')" onkeyup= "this.value=this.value.replace(/[^d.]/g, '' )" />

I have this expression here that highlights what I’m looking for /^d+(.d+)?/gm it’s just I need it completely in-versed.


The preceding expressions allow input for everything but numbers and decimals. I need to allow only numbers and decimals for input.

I have seen others but none seem to accomplish exactly what I am looking for. I don’t not want to allow negative numbers either but would like it optional.

  • 12.00 – yes
  • .124 – no
  • -.07 – no
  • -65 – no
  • 124456 – yes
  • 143467985.65534568746 – yes

Any guidance would be appreciated. Thanks for the help.


I think the expression you are looking for is /^d+(.)?d+/gm

You can view it with the test cases you provided on regex101, here

EDIT: As @Konrad Linkowski pointed out this does not work for single digits such as 1. The updated regex (^.*)+(^0*)+^d+(.d+)? includes this edge case.