在开发人员工具上获取语法错误

I'm getting an unexpected syntax error: unexpected token [

Here is my code.

$ajaxString = "";
foreach ($z as $key => $val) {
    $ajaxString .= "image[]=$val&";
}
$ajaxString = substr($ajaxString,0,-1);

$DATA .= "
    <div class='order-item-info'>
        <div class='order-item-download-all'>
            <input type='image' src='images/download-all.png' alt='Submit' onclick='download(".$ajaxString.")'>
        </div>
    </div>
";

My code on the developer tools looks like this.

<input type='image' src='download-all.png' alt='Submit' onclick='download(image[]=Logo.jpg&image[]=Logo_Large.jpg&image[]=)'>

I know I'm missing something, just can't put my finger on it.

The parameter to the download function should be a string. As it is, it is not. Change the code: (snippet)

<input type='image' src='images/download-all.png' alt='Submit' onclick='download(\"".$ajaxString."\")'>

so that it produces the following

<input type='image' src='download-all.png' alt='Submit' onclick='download("image[]=Logo.jpg&image[]=Logo_Large.jpg&image[]=")'>