Paypal all documentation

http://help.wildapricot.com/display/DOC/Requesting+PayPal+API+Signature

Drupal autocomplete suggestion click track

What I'm not sure how to do and can't seem to find online is have the form submit when a user clicks a suggestion instead of simply completing that field.

$(document).ready(function(){
Drupal.jsAC.prototype.select = function (node) {
this.input.value = $(node).data('autocompleteValue');
if(jQuery(this.input).hasClass('auto_submit')){
this.input.form.submit();
}
};
})

then on your form item add:

'#attributes' => array('class'=> array('auto_submit')),