Can’t bind to ‘target’ since it isn’t a known property of ‘div’ [duplicate]

You missed property binding

<button data-toggle="collapse" 
        [attr.data-target]="'#demo'+ RowIndex">Toggle
</button>


<button (click)="clickMe($event)">Toggle</button>

clickMe(value){
    value.srcElement.innerHTML="Clicked";

  }