jquery check if string starts with 1234

Question

Thanks for taking the time to answer my question.

I want to check if a string has exactly 7 characters and starts with \"1234\". How do I do that?

I know of

Answer 1

Simple RegExp:

var isMatch = /^1234...$/.test(myString);

Or:

var isMatch = myString.length == 7 && myString.indexOf("1234") == 0;

Edit: Or:

var isMatch = myString.length == 7 && myString.substr(0, 4) == "1234";