javascript中正则表达式反向引用示例介绍

function appendSpace(s)
{
var length = s.length;
var result = "";
var last = 0;
for(var i = 3;i<=length;i=i+3,last = last+3)
{
result = result+s.substring(i-3,i)+" ";
}
result = result+s.substring(last,length);
return result;
}

/*
*$1表示引用匹配规则中第一对括号（此处为"(.{3})"）命中的文本
*不加括号的时候会直接输出$1
*/
function insertSpace(s)
{
var result =s.replace(/(.{3})/g,"$1 ");
return result;
}