Question

I have a regex which allows only to enter integers and floats in a text box.
Regex Code:-

("^[0-9]*(?:[.][0-9]*|)$");

But it gives an error when the user enters whitespace at the beginning and end of the entered values. I want the user to allow spaces at the beginning and at the end as optional, so I changed the regex as below but it didn’t work.

Note: Spaces may be spaces or tabs.

Test Case: User might enter:

"10","10.23"," 10","10 "," 10.23","10.23 "

Any number of spaces are allowed.

("^(?:\s)*[0-9]*(?:[.][0-9]*|)$")

I am newbie with regex, so any help will be highly appreciated.

Thank you.

Answer 1

You don’t necessarily need a Regular Expression: !isNaN(Number(textboxvalue.trim())) would be sufficient.

Otherwise, try /^\s{0,}\d+\.{0,1}\d+\s{0,}$/. Test:

var testvalues = ["10","10.23"," 10","10 "," 10.23","10.23 ","10.24.25"];
for (var i=0;i<testvalues.length;i+=1){
  console.log(/^\s{0,}\d+\.{0,1}\d+\s{0,}$/.test(testvalues[i]));
}
//=> 6 x true, 1 x false