how to get the first child in html5 code example

Example 1: css first child

:first-child {
	//styles here
}

:nth-child(1) { //the benefit of this is you can do it for 2nd, 3rd etc...
	//styles here 
}

Example 2: css first

:first-of-type {
	//styles here
}

:first-child {
	//styles here
}

:nth-child(1) { //the benefit of this is you can do it for 2nd, 3rd etc...
	//styles here 
}

Example 3: first-child

p:first-child {
  background-color: yellow;
}

Example 4: how to add first child using js

var eElement; // some E DOM instance
var newFirstElement; //element which should be first in E

eElement.insertBefore(newFirstElement, eElement.firstChild);