Optimize Java Script
Impact area
Manageability
Severity
Medium
Impact
The <apex:includeScript> tag places JavaScript right before the closing </head> element, causing the browser to attempt to load the JavaScript before rendering any other content on the page. This may have unintended consequences and/or cause slower page loads.
Remediation
Use the standard HTML <script> tag instead of <apex:includeScript>.
References
See the Salesforce documentation article: Optimizing JavaScript.