try:
<script>
var re1=/^\d{6,}$/
var re2=/[\da-zA-Z]/g
alert(re1.test(1234567))
alert(re2.test("1a35"))
</script>
<script>
var re1=/^\d{6,}$/
var re2=/[\da-zA-Z]/g
alert(re1.test(1234567))
alert(re2.test("1a35"))
</script>
<script>
function check1(str)
{ return /^\d{6,}$/.test(str);}
</script>2.
<script>
function check(str)
{return /^\w*$/.test(str);}
alert(check1("1213322"));
alert(check2("asf"));
</script>
alert(s.match(/^\d{6,}$/ig)==s)
2
alert(s.match(/^[a-zA-Z0-9]+$/ig)==s)