Angular

autoSetShares(e): void {
  var elem = e.target;
  if (elem.validity.valid) {
    // is valid
  }
}

<div class="form-group m-form__group">
  <label [formCtrl]="PartnerRevenueShare">
    {{l("PartnerRevenueShare")}}
  </label>
  <div class="input-group">
    <input type="number" class="form-control"
      id="PartnerRevenueShare" name="partnerRevenueShare"
      #PartnerRevenueShare="ngModel"
      [(ngModel)]="relationship.partnerRevenueShare"
      min="0" max="100" step="1" required
      pattern="(100|[1-9][0-9]|[0-9])"
      (change)="autoSetShares($event)">
    <div class="input-group-append">
      <span class="input-group-text">
        <i class="fa fa-percent" style="color: var(--secondary)"></i>
      </span>
    </div>
  </div>
  <validation-messages [formCtrl]="PartnerRevenueShare"></validation-messages>
</div>

JQuery

var height = parseInt($('#height').val());
if (isNaN(height)) {
    return 'Please make sure you enter correct measurements.';
}

// -- OR --

function isNumeric(strString) {
    var strValidChars = "0123456789";
    var strChar;
    var blnResult = true;

    if (strString.length === 0) return false;

    for (i = 0; i < strString.length && blnResult === true; i++) {
        strChar = strString.charAt(i);
        if (strValidChars.indexOf(strChar) == -1) {
            blnResult = false;
        }
    }
    return blnResult;
}