Echo function variation with example

Echo function variation is user ” (double quote) and ‘ (single quote). but here different types of work these quotes.

Example

<?php
       $var = 10;
       // In " quotes variable value print
       echo "Value is $var";
       echo '<br />';
       // In ' quotes variable not get (print) value
       echo 'Value is $var';
?>

Output :

Value is 10
Value is $a