Wikipedia:WikiProject User scripts/Scripts/warn.js

function warn()
{
    var txt = document.editform.wpTextbox1;
var prompter = prompt("Which warning do you wish to issue?");
var msgtext = "{{subst:" + prompter + "}}~~~~";
var summary = "{{" + prompter + "}}";
    document.editform.wpSummary.value = summary;
    if(txt.value.length > 0) txt.value += '\n';
    txt.value += msgtext;
    document.editform.submit();
}