Java

Modify HTML with Javascript: https://loganelliottinfosec.com/index.php/2020/04/23/javascript-for-pentesters-task-1-modify-html-with-javascript/

Used below payload as getElementsbyTagName got H1 and H2's values and modified them.

<script>
document.getElementsByTagName('h2')[2].innerHTML = "Modified you";
document.getElementsByTagName('h1')[0].innerHTML = "Found you";
</script> 

Javascript to change form options

• Use Firefox webdev toolbar: Go to Forms -> Convert Select Elements To Text Fields, Type in Inject, click submit.

• Can use Firefox extensions like Live Http Headers, Tamperdata, or Firebug by changing the name being sent.

javascript:void(document.forms[0].name.options[0].value='Inject');void(document.forms[0].name.options[0].text='Inject')