Question

using http://www.regular-expressions.info/javascriptexample.html I tested the following regex

 ^\\{1}([0-9])+ 

this is designed to match a backslash and then a number.

It works there

If I then try this directly in code

var reg = /^\\{1}([0-9])+/;
reg.exec("/123")

I get no matches!

What am I doing wrong?

Answer 1

You need to escape the backslash in your string:

"\\123"

Also, for various implementation bugs, you may want to set reg.lastIndex = 0;.
In addition, {1} is completely redundant, you can simplify your regex to /^\\(\d)+/.
One last note: (\d)+ will only capture the last digit, you may want (\d+).