<el-form-item label="海运运费系数">

              <el-input

                v-model.trim="ruleForm.oceanFreightCoefficient"

                maxlength="8"

                @keyup.native="ruleForm.oceanFreightCoefficient=oninput(ruleForm.oceanFreightCoefficient)"

                @change="ruleForm.oceanFreightCoefficient=oninput(ruleForm.oceanFreightCoefficient)"

              ></el-input>&nbsp;&nbsp;

              <span>元/千克</span>
 </el-form-item>

oninput(num) {

          console.log(num)

            var str = num

            var len1 = str.substr(0, 1)

            var len2 = str.substr(1, 1)

            var lenLast=str.substr(str.length-1)

            //如果第一位是0，第二位不是点，就用数字把点替换掉

            if (str.length > 1 && len1 == 0 && len2 != ".") {

                str = str.substr(1, 1)

            }

            //第一位不能是.

            if (len1 == ".") {

                str = ""

            }

            //最后一位不能是.

            if (str.length==8&&lenLast == ".") {

                str = ""

            }

            //限制只能输入一个小数点

            if (str.indexOf(".") != -1) {

                var str_ = str.substr(str.indexOf(".") + 1)

                if (str_.indexOf(".") != -1) {

                    str = str.substr(0, str.indexOf(".") + str_.indexOf(".") + 1)

                }

            }

            //正则替换

            str = str.replace(/[^\d^\.]+/g, '') // 保留数字和小数点

            str = str.replace(/\.\d\d\d$/,'') // 小数点后只能输两位

            return str

}