正则语法有关问题求解释

正则语法问题求解释

JScript code

var a = 'aabbccdd';alert(a.replace(/(a.*)(?=c)/gi,'-')); //  -cddalert(a.replace(/(a.*)?(?=c)/gi,'-')); //  --cddalert(a.replace(/(a.*?)(?=c)/gi,'-')); //  -ccddalert(a.replace(/(a.*?)?(?=c)/gi,'-')); //  --c-cdd