input格式校驗（正整數）

1.只能輸入正整數：

<el-input v-model="form.residualQuantity"  @keyup.native="onlyNumber"></el-input>

//只能輸入正整數
        onlyNumber(){
          if(this.form.residualQuantity){
            this.form.residualQuantity = this.form.residualQuantity.replace(/[^\.\d]/g,'');
            this.form.residualQuantity = this.form.residualQuantity.replace('.','');
          }

        },