请问这是什么东西呢？
<input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="" /><input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwULLTIxMTQ4Mzc5ODgPZBYCAgMPZBYQAgkPPCsACQEADxYEHghEYXRhS2V5cxYAHgtfIUl0ZW1Db3VudAIJZBYSZg9kFggCAQ8PFgIeBFRleHQFAzM2NWRkAgMPDxYCHwIFATFkZAIFDw8WAh8CBeIBPGEgaHJlZj0namF2YXNjcmlwdDpGbHl0b01hcDNEKDExNy45Njk3ODUsIDI3LjY3Mzk5NCw0MDAwLDAsMCwwKTtDbG9zZVBhZ2UoIuaZr+WMuuiMg+WbtCIpO09wZW5QYWdlKCLmma/ljLrojIPlm7RcXOS5neabsua6quaZr+WMuiIpOycgY2xhc3M9InN1YnRpdGxlNCIgb25DbGljaz0iY2hhbmdlQWxsQ2xhc3MoKTt0aGlzLmNsYXNzTmFtZT0ncmVkYVN0eWxlJyI+5Lmd5puy5rqq5pmv5Yy6PC9hPmRkAgYPFQEDMzY1ZAIBD2QWCAIBDw8WAh8CBQM0NDRkZAIDDw8WAh8CBQExZGQCBQ8PFgIfAgXuATxhIGhyZWY9J2phdmFzY3JpcHQ6Rmx5dG9NYXAzRCgxMTcuOTczMDE0LCAyNy42NzgyNTIsNDAwMCwwLDAsMCk7Q2xvc2VQYWdlKCLmma/ljLrojIPlm7QiKTtPcGVuUGFnZSgi5pmv5Yy66IyD5Zu0XFzkupHnqp3igJTlpKnmuLjmma/ljLoiKTsnIGNsYXNzPSJzdWJ0aXRsZTQiIG9uQ2xpY2s9ImNoYW5nZUFsbENsYXNzKCk7dGhpcy5jbGFzc05hbWU9J3JlZGFTdHlsZSciPuS6keeqneKAlOWkqea4uOaZr+WMujwvYT5kZAIGDxUBAzQ0NGQCAg9kFggCAQ8PFgIfAgUDNDQyZGQCAw8PFgIfAgUBMWRkAgUPDxYCHwIF+gE8YSBocmVmPSdqYXZhc2NyaXB0OkZseXRvTWFwM0QoMTE3Ljk5MDMwOSwgMjcuNjcxMjE4LDQwMDAsMCwwLDApO0Nsb3NlUGFnZSgi5pmv5Yy66IyD5Zu0Iik7T3BlblBhZ2UoIuaZr+WMuuiMg+WbtFxc5q2m5aS35a6r4oCU5aSn546L5bOw5pmv5Yy6Iik7JyBjbGFzcz0ic3VidGl0bGU0IiBvbkNsaWNrPSJjaGFuZ2VBbGxDbGFzcygpO3RoaXMuY2xhc3NOYW1lPSdyZWRhU3R5bGUnIj7mrablpLflrqvigJTlpKfnjovls7Dmma/ljLo8L2E+ZGQCBg8VAQM0NDJkAgMPZBYIAgEPDxYCHwIFAzQ0MWRkAgMPDxYCHwIFATFkZAIFDw8WAh8CBfoBPGEgaHJlZj0namF2YXNjcmlwdDpGbHl0b01hcDNEKDExNy45ODgxODcsIDI3LjcwMDE2Miw0MDAwLDAsMCwwKTtDbG9zZVBhZ2UoIuaZr+WMuuiMg+WbtCIpO09wZW5QYWdlKCLmma/ljLrojIPlm7RcXOawtOW4mOa0nuKAlOWkp+e6ouiijeaZr+WMuiIpOycgY2xhc3M9InN1YnRpdGxlNCIgb25DbGljaz0iY2hhbmdlQWxsQ2xhc3MoKTt0aGlzLmNsYXNzTmFtZT0ncmVkYVN0eWxlJyI+5rC05biY5rSe4oCU5aSn57qi6KKN5pmv5Yy6PC9hPmRkAgYPFQEDNDQxZAIED2QWCAIBDw8WAh8CBQM0MjZkZAIDDw8WAh8CBQExZGQCBQ8PFgIfAgX6ATxhIGhyZWY9J2phdmFzY3JpcHQ6Rmx5dG9NYXAzRCgxMTcuOTY0NzIxLCAyNy42NjE2MTIsNDAwMCwwLDAsMCk7Q2xvc2VQYWdlKCLmma/ljLrojIPlm7QiKTtPcGVuUGFnZSgi5pmv5Yy66IyD5Zu0XFzomY7llbjlsqnigJTkuIDnur/lpKnmma/ljLoiKTsnIGNsYXNzPSJzdWJ0aXRsZTQiIG9uQ2xpY2s9ImNoYW5nZUFsbENsYXNzKCk7dGhpcy5jbGFzc05hbWU9J3JlZGFTdHlsZSciPuiZjuWVuOWyqeKAlOS4gOe6v+WkqeaZr+WMujwvYT5kZAIGDxUBAzQyNmQCBQ9kFggCAQ8PFgIfAgUDNzY4ZGQCAw8PFgIfAgUBMWRkAgUPDxYCHwIFhQI8YSBocmVmPSdqYXZhc2NyaXB0OkZseXRvTWFwM0QoMTE3LjY5NzI1LCAyNy43NzI4MzQsNDAwMCwwLDAsMCk7Q2xvc2VQYWdlKCLmma/ljLrojIPlm7QiKTtPcGVuUGFnZSgi5pmv5Yy66IyD5Zu0XFzmrablpLflsbHlm73lrrbnuqfoh6rnhLbkv53miqTljLoiKTsnIGNsYXNzPSJzdWJ0aXRsZTQiIG9uQ2xpY2s9ImNoYW5nZUFsbENsYXNzKCk7dGhpcy5jbGFzc05hbWU9J3JlZGFTdHlsZSciPuatpuWkt+WxseWbveWutue6p+iHqueEtuS/neaKpOWMujwvYT5kZAIGDxUBAzc2OGQCBg9kFggCAQ8PFgIfAgUDNzcxZGQCAw8PFgIfAgUBMWRkAgUPDxYCHwIF7QE8YSBocmVmPSdqYXZhc2NyaXB0OkZseXRvTWFwM0QoMTE4LjA2NTY5NiwgMjcuNjk1ODYsNDAwMCwwLDAsMCk7Q2xvc2VQYWdlKCLmma/ljLrojIPlm7QiKTtPcGVuUGFnZSgi5pmv5Yy66IyD5Zu0XFzkuIvmooXlj6TmsJHlsYXmma/ljLoiKTsnIGNsYXNzPSJzdWJ0aXRsZTQiIG9uQ2xpY2s9ImNoYW5nZUFsbENsYXNzKCk7dGhpcy5jbGFzc05hbWU9J3JlZGFTdHlsZSciPuS4i+aiheWPpOawkeWxheaZr+WMujwvYT5kZAIGDxUBAzc3MWQCBw9kFggCAQ8PFgIfAgUDNzcyZGQCAw8PFgIfAgUBMWRkAgUPDxYCHwIFiAI8YSBocmVmPSdqYXZhc2NyaXB0OkZseXRvTWFwM0QoMTE3Ljc5MjY2MiwgMjcuNjk1NzgzLDI1MzQuMTU2MjQyLDM1Ni42MDU0MSwyNzEuMDAwMjQyLDApO0Nsb3NlUGFnZSgi5pmv5Yy66IyD5Zu0Iik7T3BlblBhZ2UoIuaZr+WMuuiMg+WbtFxc5aSn5bOh6LC35ryC5rWB5pmv5Yy6ICIpOycgY2xhc3M9InN1YnRpdGxlNCIgb25DbGljaz0iY2hhbmdlQWxsQ2xhc3MoKTt0aGlzLmNsYXNzTmFtZT0ncmVkYVN0eWxlJyI+5aSn5bOh6LC35ryC5rWB5pmv5Yy6IDwvYT5kZAIGDxUBAzc3MmQCCA9kFggCAQ8PFgIfAgUDNzc1ZGQCAw8PFgIfAgUBMWRkAgUPDxYCHwIF7QE8YSBocmVmPSdqYXZhc2NyaXB0OkZseXRvTWFwM0QoMTE3Ljk5NTA1LCAyNy42NzUxNDcsNDAwMCwwLDAsMCk7Q2xvc2VQYWdlKCLmma/ljLrojIPlm7QiKTtPcGVuUGFnZSgi5pmv5Yy66IyD5Zu0XFzmrablpLflsbHmvILmtYHmma/ljLoiKTsnIGNsYXNzPSJzdWJ0aXRsZTQiIG9uQ2xpY2s9ImNoYW5nZUFsbENsYXNzKCk7dGhpcy5jbGFzc05hbWU9J3JlZGFTdHlsZSciPuatpuWkt+Wxsea8gua1geaZr+WMujwvYT5kZAIGDxUBAzc3NWQCCw8PFgIfAgUY5b2T5YmN56ysMS8y6aG1IOWFsTE45p2hZGQCDw8PFgIeB0VuYWJsZWRoZGQCFw8PFgIeB1Zpc2libGVoZGQCGQ8PFgIfBGhkZAIbDw8WAh8EaGRkAh0PDxYCHwRoZGQCHw8PFgIfBGhkZGQ/NXX3MSzOFpb7XUg1Zbyrp2YI3w==" />
