写js 时输入框限制只能输入金额包含小数

 {
               if (text != null && text.length >=15) {
                   Toast.show("总金额不能超过15位数",1000)
               }else {
                   let newmoney = this.state.money
                   try {
                       let a =Number(text)
                       if (isNaN(a)) {
                           this.setState({
                               money: newmoney.trim()
                           })
                       }else {
                           this.setState({
                               money: text.trim()
                           })
                       }
                   }catch (e) {
                       this.setState({
                           money: newmoney.trim()
                       })
                   }
               }
           }}/>