Vuejs realizes onchange function with watch

The results to be achieved in the project are as follows:

Asked to move to the left to achieve the rotation of the picture, the first thought of the onchange event, but the view Vue document did not find the Onchang command, so think of the Vue watch hook to monitor the changes in the sliding value, thus invoking the rotation function of the component.

The code is as follows:

<input id= "Defaultslider" v-model= "Rotateval" type= "range" min= "0" max= "/>"

1.v-model= the "rotateval" binding value into data.

data () {return{ID:‘‘, Name:‘‘, Coverpic:‘‘, Iptlist: [], Input:false, Image:false, IsEmpty:true, Requirelist:‘‘, data: {data: {}, Appid:api.appid, ID:‘‘}, Inputs: {}, Imgsrc:‘‘, Cropimg:imgurl, crop:‘‘, Cropper:false, Rotateval:0      }    },

2.watch Monitoring Rotateval

Watch: {      function  (newval, oldval) {        this. Rotate (oldval)      }    },

3. Rotation and cropping by component

Rotate (val) {        this. $refs. Cropper.rotate (val);      },

Vuejs realizes onchange function with watch