SVG: text inside rect

Programmatically using D3:

body = d3.select('body')
svg = body.append('svg').attr('height', 600).attr('width', 200)
rect = svg.append('rect').transition().duration(500).attr('width', 150)
                .attr('height', 100)
                .attr('x', 40)
                .attr('y', 100)
                .style('fill', 'white')
                .attr('stroke', 'black')
text = svg.append('text').text('This is some information about whatever')
                .attr('x', 50)
                .attr('y', 150)
                .attr('fill', 'black')

This is not possible. If you want to display text inside a rect element you should put them both in a group with the text element coming after the rect element ( so it appears on top ).

<svg xmlns="http://www.w3.org/2000/svg">
  <g>
    <rect x="0" y="0" width="100" height="100" fill="red"></rect>
    <text x="0" y="50" font-family="Verdana" font-size="35" fill="blue">Hello</text>
  </g>
</svg>