All PHP code must be enclosed inside <? and ?> closing tags
echo outputs text.
<?
$a=1;
echo $a;
?>
will display the value of $a which is 1
<?
$a=5;
echo "Display this text $a=$a";
?>
will display whatever is between the double quotes including the value of variables. Notice the \ used in the statement. The \ will escape the next character. Using a \ before special characters like " $ display the character. Using \
echo 'Displays this text $a'; Displays everything inside single quotes. Variables are not interpreted. The example above displays as Displays this text $a.