Javascript RegEx - Start and End of String Anomalies

Question

So im trying some really basic RegEx out for the first time and I've been told that theres a few ways of stating the start and end of the string.

One way would be ' \\A ' & ' \\Z ' and the other would be ' ^ ' & ' $ '.

For some reason when running this in JS, the later is the only option that actually works.

Does anyone know why that might be please?

var str = "123456",
    pattern1 = new RegExp("^\\d{6}$"),
    pattern2 = new RegExp("\A\\d{6}\Z");

if(pattern1.test(str)){
    alert('pattern 1 match!'); 
}else{
    alert('pattern 1 no match!'); 
}

if(pattern2.test(str)){
    alert('pattern 2 match!'); 
}else{
    alert('pattern 2 no match!'); 
}

Answer 1

I think whoever told you that \\A and \\Z are supposed to work was misinformed. Based on the JavaScript Regular Expressions documentation , only ^ and $ should work.

Answer 2

Have a little play with a regex visualizer, like Debuggex . It shows that your expression matches when PCRE or Python is selected as the regex flavor (in the drop-down), but doesn't match when using the Javascript flavor.

In short, Javascript simply doesn't support \\A and \\Z .