话不多说，上代码
<input type="tel" v-model="telephone" maxlength="13">
js部分
data () {
return {
telephone: ''
}
},
watch: {
telephone (newValue, oldValue) {
if (newValue > oldValue) {
if (newValue.length === 4 || newValue.length === 9) {
var pre = newValue.substring(0, newValue.length - 1)
var last = newValue.substr(newValue.length - 1, 1)
this.telephone = pre + ' ' + last
} else {
this.telephone = newValue
}
} else {
if (newValue.length === 9 || newValue.length === 4) {
this.telephone = this.telephone.trim()
} else {
this.telephone = newValue
}
}
}
},
