如果（作者）声明在Joomla 1.5中

i need php based if loop where i can in Joomla 1.5 HTML insert php code to find author and when i get that variable i can make IF statement

for example

if ($author="a") {
echo "This is author a";
}

elseif ($author="b"){
echo "this is author b";
}

elseif ($author="c"){
echo "this is author c";
}

I do not know how get $author variable (name) from article

You should use == or === instead of = in if statements

Example

if ($author == "a") {
    echo "This is author a";
} 

elseif ($author == "b") {
    echo "this is author b";
} 

elseif ($author == "c") {
    echo "this is author c";
}

Or Use Switch

switch ($author) {
    case "a" :
        echo "This is author a";
        break;
    case "b" :
        echo "This is author a";
        break;
    case "c" :
        echo "This is author a";
        break;
}