Edit in JSFiddle

var array = [ 1, 2, 3, 4, 5, 6, 7 ];

// 4 삭제
var removedArray = array.splice( 3, 1 );

document.write( "array" );
for( let vari in array ) {
	document.write( "<li>" + array[ vari ] + "</li>" );
}

document.write( "<br><br>" );
document.write( "removedArray" );
for( let vari in removedArray ) {
	document.write( "<li>" + removedArray[ vari ] + "</li>" );
}