Oninput regular express match to digit before decimal and after decimal

<pre lang="HTML">
<input type="text" class="form-control" name="component_gst_percent" id="component_gst_percent{{@$capexItem->po_item_config_id}}" value="{{@$capexItem->component_gst_percent}}" placeholder="Enter GST"  onkeydown="javascript: return event.keyCode == 69 ? false : true" oninput="this.value = this.value.replace(/[^0-9.]/g, '').replace(/(\..*?)\..*/g, '$1').replace(/(\.\d{2}).+/g, '$1');">

function checkInput(data){
              let gst_input=data.value;
              let regex=new RegExp("^\\d{0,2}$|(?=^.{0,5}$)^\\d+\\.\\d{0,2}$");
              if (!regex.test(gst_input)) {
                  console.log('fail');
                  return false;
              }
              return true;
          }