为什么这些返回null
:
var str="Is this all abc bbb c is";
var patt1=/is(?=bbb)/;
var str="Is this all abc bbb c is";
var patt1=/is(?=bbb)/;
var str="Is this all there is";
var patt1=/is(?=all)/; // <------ (?=all) vs (? =all)
但这会返回is
:
var str="Is this all there is";
var patt1=/is(?= all)/;
?