<ui-textbox label="initial" v-model="initial_cost"
    name="initial_cost"
    v-validate="`numeric|decimal`"
    type="number"
    v-on:keydown="isNumber"
    :maxlength = "18"
    :enforceMaxlength="true"
    value = 0.00
    format="number"
></ui-textbox>

isNumber: function(evt) {
        evt = (evt) ? evt : window.event;
        var charCode = (evt.which) ? evt.which : evt.keyCode;
        var charval= String.fromCharCode(evt.keyCode);
        console.log(typeof evt);
        if((charCode >= 48 && charCode <= 57) || (charCode >= 96 && charCode <= 105) || charCode == 8 || charCode == 46 ||
        charCode ==36 || charCode ==35){
            return true;
        }else{
            return false;
        }