javascript - Regex for a number which can starts with 0 -

i use regex field:

/^([1-9]([0-9]){0,3}?)((\.|\,)\d{1,2})?$/; 

what want allow user enter 0 beginning of number, in cas, must enter @ least second digit diffrent 0 , same rule applied third , fourth digits.

example:

• 01 -> valid
• 00 -> not valid
• 0 -> not valid
• 1 -> valid

in short, 0 value must not allowed. how can using regex? or better if javascript script?

if want match numbers have 1 4 digits in part before decimal separator, , 2 digits after decimal separator (i deduce regex used) and not start 00 (that requirement comes verbal explanation), use

/^(?!00)(?!0+(?:[.,]0+)?$)\d{1,~4}(?:[.,]\d{1,2})?$/ 

see regex demo.

details

• ^- start of string
• (?!00) - no 2 0s @ start of string
• (?!0+(?:[.,]0+)?$) - negative lookahead fails match if there 1 or more 0s, followed optional sequence of . or , followed 1 or more zeros string end
• \d{1,4} - 1 4 digits
• (?:[.,]\d{1,2})? - 1 or 0 occurrences of
  • [.,] - . or ,
  • \d{1,2} - 1 or 2 digits
• $ - end of string.

js demo:

var ss = ['1','1.1','01','01.3','023.45','0','00','0.0','0.00','0001'];  var rx = /^(?!00)(?!0+(?:[.,]0+)?$)\d{1,4}(?:[.,]\d{1,2})?$/;  (var s of ss) {   var result = rx.test(s);   console.log(s, "=>", result);  }

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