如何用正则获取第二个双引号间的内容，不包括双引号

[暮暮白白]

{"mokuai4.jpg":"photos/15270452376978833.jpg","isSuccess":true} 我需要获得 photos/15270452376978833.jpg，这个正则怎么写？

[老鼠拧刀满街找猫]

var obj=JSON.parse('{"mokuai4.jpg":"photos/15270452376978833.jpg","isSuccess":true}');
obj["mokuai4.jpg"];

[文盲老顾]

'{"mokuai4.jpg":"photos/15270452376978833.jpg","isSuccess":true}'.match(/([^"]+)(?="(?=[,\}]))/gi)

[functionsub]

var str = '{"mokuai4.jpg":"photos/15270452376978833.jpg","isSuccess":true}';
var reg = /"([^"]+)"/g;
var arr = [];
str.replace(reg,function(v1,v2){
    arr.push(v2);
})

console.log(arr[1])