H93 (Pass): Ensuring that id attributes are unique on a Web page

HTML Snippet Code
Scenario 1: Unique ID values




<label for="uname1">Firstname</label> <input id="uname1" type="text" ></br> <label for="ln1">Lastname</label> <input input id="ln1" type="text" ></br> <label for="em1">Email</label> <input input id="em1" type="text" ></br> <label for="ps1">password</label> <input input id="ps1" type="text" ></br> <button id="btnsubmit1">submit</button> <button id="btncancel1">Cancel</button>
Scenario 2: Disable elements having same ID value




<label for="uname2">Firstname</label> <input id="uname2" type="text" ></br> <label for="ln2">Lastname</label> <input input id="ln2" type="text" ></br> <label for="em2">Email</label> <input input id="em2" type="text" ></br> <label for="ps2">password</label> <input input id="ps2" type="text" ></br> <button id="btn2">submit</button> <button id="btn2_1" style="display:none">Cancel</button>
Scenario 3: Same ID values used for script element




<script id="script1" type="text/javascript" src="scripts1.js"></script> <script id="script2" type="text/javascript" src="scripts2.js"></script> <label for="uname3">Firstname</label> <input id="uname3" type="text" ></br> <label for="ln3">Lastname</label> <input input id="ln3" type="text" ></br> <label for="em3">Email</label> <input input id="em3" type="text" ></br> <label for="ps3">password</label> <input input id="ps3" type="text" ></br> <button id="btnsubmit3">submit</button> <button id="btncancel3">Cancel</button>