How to show a child div without changing the position of that element's siblings?

Question

I have a div html tag from a login form, with a div inside that form that shows an error. The error div is at the top of the parent div. When the error is triggered, I want the error div to be inside the form div, without the form going down, but that is not what happens. I've already used position: absolute in the child div, but it stays in the left corner of the parent div. I've also used z-index too, so that the child div is over the parent div, but the parent always descends a pixel height the size of the child div. Let me show you the example:

<div id='formulario'  style={{height: 400px}}>
    {this.props.auth.error && <div id='erro'  style={{height:'15px'}}>Nao foi possivel fazer o login!</div>}
    <div id='login'>
    ...
   </div>
</div>

When this.props.auth.error is true, the error appears and the form id size becomes 415px. How do I leave the #formulatrio div with the size of 400px and the #login div in place when the error appears?

Answer 1

Just for you to test I added the background.

<style>
    #formulario {
        display: grid;
        align-content: center;
        width: 400px;
        height: 400px;
        background: grey;
    }
    #erro {
        position: relative;
        width: 100%;
        height: 15px;
        background: yellow;
        text-align: center;
    }
</style>

<div id='formulario'>
    {this.props.auth.error && <div id='erro'>Nao foi possivel fazer o login!</div>}
    <div id='login'>
        ...
    </div>
</div>

Answer 2

increase the top CSS property to move the login div down to a certain position, added background for visualization.

 class MaintainPosition extends React.Component { render() { return ( <div id="formulario" style={{ height: "400px", backgroundColor: "lightblue" }} > {this.props.auth.error && ( <div id="erro" style={{ height: "15px", color: "red" }}> Nao foi possivel fazer o login! </div> )} <div id="login"> scroll down to toggle error </div> </div> ); } } class App extends React.Component { constructor(props) { super(props); this.state = { error: true }; } render() { return ( <div className="App"> <MaintainPosition auth={{ error: this.state.error }} /> <button onClick={() => this.setState({ error: !this.state.error })}> toggle error </button> </div> ); } } const rootElement = document.getElementById("root"); ReactDOM.render(<App />, rootElement); 

 #err { } #formulario { position: relative; } #login { position: absolute; width: 100%; top: 20px; background-color: gray; } #root {text-align: center} 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script> <div id="root"></div> 

Answer 3

Something like this?

Key here is to set the parent to relative so the child knows what to use a reference.

 $('button').on('click', function() { $('#erro').toggle(); }); 

 #formulario { border: 1px solid #EEE; position: relative; } #erro { background-color: rgba(255,0,0,.5); text-align: center; position: absolute; width: 100%; } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <button>Show/Hide Error</button> <hr> <div id='formulario' style='height: 400px'> <div id='erro' style='height: 15px'>Nao foi possivel fazer o login!</div> <div id='login'> Some<br/> Login<br/> Stuff<br/> </div> </div>