获取隐藏的单选按钮值并使用ajax插入表单

I have two radio buttons where user can select the user type. The radio buttons are hidden and I am using images instead of the original design. What I am trying to do is to set the default value of the radio button checked onLoad, so the user doesn't have to make an extra click. I tried setting the radio button checked in HTML, but the value is not being passed, since I have the var value; as a parameter for formData.I have two radio buttons where user can select