function ncsdn(a, b, c) {
if (b.indexOf("csdn") > -1) return;
else return a;
}
var pat = /(([a-z]|\d)+)/gi;
var strng = "search 900 csdn 1200 net";
var nstrng = strng.replace(pat, ncsdn);
nstrng = nstrng.match(pat).join("\n");
alert(nstrng);
</script>
if (b.indexOf("csdn") > -1) return;
else return a;
}
var pat = /(([a-z]|\d)+)/gi;
var strng = "search 900 csdn 1200 net";
var nstrng = strng.replace(pat, ncsdn);
nstrng = nstrng.match(pat).join("\n");
alert(nstrng);
</script>
这样也许效率会高点吧
var str="search 900 csdn 1200 net";
re = /\b(?!(csdn))[A-Za-z0-9]+\b/ig;
alert(str.match(re));
</script>