php验证码实现代码

public function get_code(){
		header("content-type:image/jpeg");
		//session_start();
	
		$img = imagecreatetruecolor(75,25);
	
		$bg = imagecolorallocate($img,rand(100,255),rand(100,255),rand(100,255));
		imagefilledrectangle($img,0,0,75,25,$bg);
	
		$str = "";//存储验证码
		$trueCode = "";//真实的验证码
		for($i=0;$isession->set_userdata(array('myCode'=>$trueCode));
		// 	/echo $trueCode;
		$fg = imagecolorallocate($img,rand(0,50),rand(0,150),rand(0,150));
		imagestring($img,6,5,5,$str,$fg);
	
		for($i=0;$i

Security Code:
		
		?random='+Math.random();" align="absmiddle" alt="Can't see?Change it!" title="Can't see?Change it!"/>