Simple test that the dragstart event contains the default data in the event.

Select some text in this box and drag it.

Drag the image. 

Drag the link. Link

Test ID: selectionTest
text/plain: Select some text in this box and drag it.
text/url:
text/html: <span style="color: rgb(0, 0, 0); font-family: serif; font-size: medium; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; white-space: normal; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">Select some text in this box and drag it.</span>
Test ID: imageTest
text/plain:
text/url:
text/html: <img id="imageTest" src="data:image/png;base64,%0A iVBORw0KGgoAAAANSUhEUgAAAJYAAAA8CAIAAAAL5NQ9AAAACXBIWXMAAAsTAAALEwEAmpwY%0A AAAAB3RJTUUH2woaBQc4oLEFpAAAABl0RVh0Q29tbWVudABDcmVhdGVkIHdpdGggR0lNUFeB%0A DhcAAACMSURBVHja7dNBEYAgFEVRPhHMYgAzUIsmVnFvB/fsoQb+ObfBmzMvxneW1D1vzz2w%0A FiEUQiFEKIRCKIQIhVAIhRChEAqhECIUQiEUQoRCKIRCiFAIhVAIEep3xTWTLzzu5oVCKIRC%0A iFAIhVAIEQqhEAohQiEUQiFEKIRCKIQIhVAIhRChEAqhECLUZi3VEwcBMGr1NgAAAABJRU5E%0A rkJggg==" ondragstart="dragStartTest(event)">
Test ID: linkTest
text/plain: http://www.example.com/
text/url:
text/html: <a id="linkTest" href="http://www.example.com/" ondragstart="dragStartTest(event)">Link</a>