4.编写一个死循环，注册两个观察者，对同一个变量进行修改。

[zhufengnodejs]

[null64]

error: [$rootScope:infdig] 10 $digest() iterations reached. Aborting!
Watchers fired in the last 5 iterations: [[{"msg":"age","newVal":618,"oldVal":616},{"msg":"age","newVal":619,"oldVal":617},{"msg":"fn: ngModelWatch","newVal":620,"oldVal":618},{"msg":"fn: regularInterceptedExpression","newVal":"620","oldVal":"618"}],[{"msg":"age","newVal":620,"oldVal":618},{"msg":"age","newVal":621,"oldVal

[Leconomy]

Error: [$rootScope:infdig] 10 $digest() iterations reached. Aborting!
Watchers fired in the last 5 iterations: [[{"msg":"age","newVal":112,"oldVal":110},{"msg":"age","newVal":113,"oldVal":111},{"msg":"fn: ngModelWatch","newVal":114,"oldVal":112},{"msg":"fn: regularInterceptedExpression","newVal":"114","oldVal":"112"}],[{"msg":"age","newVal":114,"oldVal":112},{"msg":"age","newVal":115,"oldVal":113},{"msg":"fn: ngModelWatch","newVal":116,"oldVal":114},{"msg":"fn: regularInterceptedExpression","newVal":"116","oldVal":"114"}],[{"msg":"age","newVal":116,"oldVal":114},{"msg":"age","newVal":117,"oldVal":115},{"msg":"fn: ngModelWatch","newVal":118,"oldVal":116},{"msg":"fn: regularInterceptedExpression","newVal":"118","oldVal":"116"}],[{"msg":"age","newVal":118,"oldVal":116},{"msg":"age","newVal":119,"oldVal":117},{"msg":"fn: ngModelWatch","newVal":120,"oldVal":118},{"msg":"fn: regularInterceptedExpression","newVal":"120","oldVal":"118"}],[{"msg":"age","newVal":120,"oldVal":118},{"msg":"age","newVal":121,"oldVal":119},{"msg":"fn: ngModelWatch","newVal":122,"oldVal":120},{"msg":"fn: regularInterceptedExpression","newVal":"122","oldVal":"120"}]]

[zhufengnodejs]

rror: [$rootScope:infdig] 10 $digest() iterations reached. Aborting!
Watchers fired in the last 5 iterations: [[{"msg":"age","newVal":618,"oldVal":616},{"msg":"age","newVal":619,"oldVal":617},{"msg":"fn: ngModelWatch","newVal":620,"oldVal":618},{"msg":"fn: regularInterceptedExpression","newVal":"620","oldVal":"618"}],[{"msg":"age","newVal":620,"oldVal":618},{"msg":"age","newVal":621,"oldVal