Question

I am trying to validate a variable contains a 9-digit number in Javascript. This should be basic but for some reason this is failing:

    var test = "123123123";
    var pattern = new RegExp("/\d{9}/");

    if(test.match(pattern))
    {
        //This code never executes
    }
    else
    {
        //This code is always executing
        alert('no match!'); 
    }

Can anyone see why I am not getting a match?

I also tried type-casting test to an integer with:

test = Number(test);

…but this doesn’t work as it has to be a String to support the .match method.

Answer 1

You’re mixing the two different regex constructors. Pick one:

 var pattern = new RegExp("^\\d{9}$");
 // or
 var pattern = /^\d{9}$/;

N.B. you probably want to add start and end anchors (as above) to make sure the whole string matches.