Regular Expression For Validating Decimal Numbers

function validateDecimal(number,maxDigits) { eval('var stringvar=/^[-+]?([0-9]*\.[0-9]{0,'+maxDigits+'})|([0-9]+)$/'); return stringvar.test(number); } I wrote above fun

Solution 1:

Without going into the regex, I think the problem in your code is that you should escape the special character twice. Since you're putting it all inside a string, a single backslash is escaped by the string parsing.

I think this should work:

eval("var stringvar=/^[-+]?([0-9]*\\.[0-9]{0,"+maxDigits+"})|([0-9]+)$/");

Solution 2:

This regular expression would validate a number with maxDigits of decimals: ^[-+]?[0-9]*.[0-9]{10}$. This will validate it to 10 decimal places.

Implementing that into JavaScript would look like: eval("var stringvar=^[-+]?[0-9]*.[0-9]{" + maxDigits + "}$");, or thereabouts.

Solution 3:

I have just tried this one and it worked for me: ^[+-]?[0-9]*(\.[0-9]{0,5})?$.

In my case I made a minor modification, you seem to be matching either a decimal number or else a whole number. In my case, I modified the regular expression to take a whole number with an optional decimal section.

As is, the regular expression will match values like: .222, 23.22222 but not 4d.22222, 33.333333, etc.

var n1 = "4.33254";
var n2 = "4d.55";

eval("var stringvar=/^[+-]?[0-9]*(\\.[0-9]{0,5})?$/");
alert(stringvar.test(n1));
alert(stringvar.test(n2));

Yielded: true and false respectively.