Syntax error in Javascript pattern

I'm getting a syntax error in this simple javascript code. I just want to check the atring on a pattern. Can any one tell me what is wrong?

var a = 'test@server开发者_StackOverflow社区.com';
var pattern = [a-zA-Z0-9_]+[.[a-zA-Z0-9]+]*@[a-zA-Z0-9_]+[.[a-zA-Z]+]+;
console.log('The comparison is ',a.match(pattern));

Thanks.

Try

var pattern = /[a-zA-Z0-9_]+[.[a-zA-Z0-9]+]*@[a-zA-Z0-9_]+[.[a-zA-Z]+]+/;

Patterns are usually delimited by //. See RegExp on MDC.

try

 var pattern = /^[a-zA-Z0-9_]+[.[a-zA-Z0-9]+]*@[a-zA-Z0-9_]+[.[a-zA-Z]+]+$/;

you have no delimiter on the pattern. Have you tried

var pattern = '[a-zA-Z0-9_]+[.[a-zA-Z0-9]+]*@[a-zA-Z0-9_]+[.[a-zA-Z]+]+';

?