html difference between equal sign and colon -

what difference between using = , : when assigning value in attribute? example:

<p style="width=100px, height:1000px"></p> 

does have reliable source tells difference between 2 , appropriate usage?

= used assign values attributes in html elements. : used assign values css based properties.

example

html

<p id="p1" height="100px"> 

css

body{ background-color:red; } 

in example <p style="width=100px..." wrong , given value style attribute = css properties in style attribute values using : only. cannot separate css properties , , have use ; separate them. correct version

<p style="width:100px; height:1000px"></p>