Trick how to make Select control as readonly using jQuery but not disabled
There's a control <select> on your page and you want to use it's value as selected and don't want to allow user to change it. Unfortunately, there's no attribute "readonly" for select as for <input> ones. You can use only attribute "disabled", but in this case its value will not be sent. But there's a trick how to do it.
First you should add attribute "disabled" and set it to "true". In this case after sending your form the value will not be sent to a server. But you can change the value of attribute before sending the form! You should just set the value of attribute "disabled" to false.
So, you should change attribute "disabled" value just before submitting.
For example, for SharePoint forms it you should override function OnPreSaveItem().