Checkout their documentation and scroll down to "Single Address": https://blockchain.info/api/blockchain_api
https://blockchain.info/address/$bitcoin_address?format=json
Using this you can get the balance in JSON format and parse it with PHP.
//Declare an address as a variable
$btc_address = "1J9ikqFuwrzPbczsDkquA9uVYeq6dEehsj";
//Get the balance using blockchaininfo API
$addr_url = "https://blockchain.info/address/$btc_address?format=json";
$json_addr = json_decode(file_get_contents($addr_url), true);
$balance = $json_addr["final_balance"];
//Display the balance on the screen in satoshis
echo $balance;
//Display on the screen as bitcoins
$con_bal = $balance / 100000000;
echo "
". $con_bal;
thank you so much for helping me