无法在JS中添加PHP [重复]

Question

This question already has an answer here:

• How to print JavaScript with PHP 3 answers

I am trying to add a PHP code to echo a text inside of JavaScript but when I try the code it's don't echo the text it echoes 0

<script>
window.onload = function(){
    <?php if (empty($dark_mode)){ echo '$('*').toggleClass("light") document.getElementById("*").classList.remove("dark");';}else{ echo '$('*').toggleClass("light")  document.getElementById("*").classList.remove("light");';} ?>
};
</script>

</div>

Answer 1

i had the same issue on past i did use php to print all javascript with php vars too , in your case it well be :

     <?php
     echo "<script>";
     echo "window.onload = function(){";
     if (empty($dark_mode)){
              echo "$('*').toggleClass('light') document.getElementById('*').classList.remove('dark');";
     }else{ 
     echo "$('*').toggleClass('light') document.getElementById('*').classList.remove('light');";
     }

echo ""; ?>