Regex for empty string or white space

Question

I am trying to detect if a user enter whitespace in a textbox:

 var regex = "^\s+$" ;   if($("#siren").val().match(regex)) {      echo($("#siren").val());      error+=1;     $("#siren").addClass("error");     $(".div-error").append("- Champ Siren/Siret ne doit pas etre vide<br/>");  } 

if($("#siren").val().match(regex)) is supposed to match whitespace string, however, it doesn' t seems to work, what am I doing wrong ?

Thanks for your helps

Answer 1

The \ (backslash) in the .match call is not properly escaped. It would be easier to use a regex literal though. Either will work:

var regex = "^\\s+$"; var regex = /^\s+$/; 

Also note that + will require at least one space. You may want to use *.

Answer 2

If you are looking for empty string in addition to whitespace you meed to use * rather than +

var regex = /^\s*$/ ;                 ^