比如,原字符串为pt.setHeader({"2420524895":"http:\/\/q4.qlogo.cn\/g?b=qq&k=eEQWdib29NoVuiaqtahiae8qA&s=100&t=1434879769"});想提取的字符串为:http:\/\/q4.qlogo.cn\/g?b=qq&k=eEQWdib29NoVuiaqtahiae8qA&s=100&t=1434879769该怎么做呢?最好有具体的代码怎么取冒号后面引号里的值?