I have created a regular expression in C# that I am using in model validations. I need same in JavaScript. Please help me to convert.

Here is the regular expression in C#

[Required]
[Display(Name = "Cost")]
[DataType(DataType.Currency)]
[RegularExpression(@"^(([a-zA-Z]+)|(\d{0,15}.\d{0,2}))$", ErrorMessage = "Cost can not have more than 2 decimal places.")]
[Range(typeof(Decimal), "0.01", "99999999999999.99", ErrorMessage = "{0} must be a decimal/number greater than 0 and less than 100000000000000.")]
public Nullable<decimal> Cost { get; set; }

And one more validation message "Field must be a number"

I am trying like this in javascript

var regExp = new RegExp("(([a-zA-Z]+)|(\d{0,15}.\d{0,2}))");
var res = regExp.test($('#Cost').val());

But this always returns true

Thanks

I have created a regular expression in C# that I am using in model validations. I need same in JavaScript. Please help me to convert.

Here is the regular expression in C#

[Required]
[Display(Name = "Cost")]
[DataType(DataType.Currency)]
[RegularExpression(@"^(([a-zA-Z]+)|(\d{0,15}.\d{0,2}))$", ErrorMessage = "Cost can not have more than 2 decimal places.")]
[Range(typeof(Decimal), "0.01", "99999999999999.99", ErrorMessage = "{0} must be a decimal/number greater than 0 and less than 100000000000000.")]
public Nullable<decimal> Cost { get; set; }

And one more validation message "Field must be a number"

I am trying like this in javascript

var regExp = new RegExp("(([a-zA-Z]+)|(\d{0,15}.\d{0,2}))");
var res = regExp.test($('#Cost').val());

But this always returns true

Thanks

• javascript
• c#
• regex

• I'd suggest using JavaScript's built-in regex syntax to avoid string escaping issues: var regExp = /^(([a-zA-Z]+)|(\d{0,15}.\d{0,2}))$/; – cdhowie Commented Oct 10, 2014 at 6:43

2 Answers 2

If you're trying to verify that cost must contain 2 decimal places, then take out the "or" part in your regex that matches any alpha string:

^(\d{0,15}\.\d{0,2})$

Note: You also don't need parenthesis since you're not going to do anything with the captured value here.

The regex you mentioned will fail in C# as well, but you get the illusion of it working because of your Range attribute.

And finally, if you're using new Regexp syntax, you need to escape the slashes:

var re = new RegExp("^\\d{0,15}\\.\\d{0,2}$");

// or using shorter JS syntax
var re = /^\d{0,15}\.\d{0,2}$/;

Sample runs:

console.log(re.test("abc"));  // false
console.log(re.test("10.23"));  // true
console.log(re.test("10"));  // false

To avoid your problem use JavaScript syntax and as already mentioned you you should escape the decimal dot (\.) or use [\.,] to match a ma too (the given example will also match 123W4):

var regExp = /(([a-zA-Z]+)|(\d{0,15}\.\d{0,2}))/;