This simply produces a link whose text cycles between a number of values whenever you click on it. It otherwise leads nowhere. You can use it as a silly clicky trinket, a cheap alternative to the <<replace>> macro, or (as detailed below) as an input interface element.

version.extensions.cyclinglinkMacro={major:3,minor:3,revision:0};
macros.cyclinglink={handler:function(a,b,c){var rl="cyclingLink";
function toggleText(w){w.classList.remove("cyclingLinkInit");
w.classList.toggle(rl+"Enabled");w.classList.toggle(rl+"Disabled");
w.style.display=((w.style.display=="none")?"inline":"none")}switch(c[c.length-1]){case"end":var end=true;
c.pop();break;case"out":var out=true;c.pop();break}var v="";if(c.length&&c[0][0]=="$"){v=c[0].slice(1);
c.shift()}var h=state.history[0].variables;if(out&&h[v]===""){return
}var l=Wikifier.createInternalLink(a,null);l.className="internalLink cyclingLink";
l.setAttribute("data-cycle",0);for(var i=0;i<c.length;i++){var on=(i==Math.max(c.indexOf(h[v]),0));
var d=insertElement(null,"span",null,"cyclingLinkInit cyclingLink"+((on)?"En":"Dis")+"abled");
if(on){h[v]=c[i];l.setAttribute("data-cycle",i)}else{d.style.display="none"
}insertText(d,c[i]);if(on&&end&&i==c.length-1){l.parentNode.replaceChild(d,l)
}else{l.appendChild(d)}}l.onclick=function(){var t=this.childNodes;
var u=this.getAttribute("data-cycle")-0;var m=t.length;toggleText(t[u]);
u=(u+1);if(!(out&&u==m)){u%=m;if(v){h[v]=c[u]}}else{h[v]=""}if((end||out)&&u==m-(end?1:0)){if(end){var n=this.removeChild(t[u]);
n.className=rl+"End";n.style.display="inline";this.parentNode.replaceChild(n,this)
}else{this.parentNode.removeChild(this);return}return}toggleText(t[u]);
this.setAttribute("data-cycle",u)}}};

If the first parameter begins with the "$" sigil, then it will interpret it as a variable to be altered by clicking the link. When the player visits the page or clicks the link, the variable will be changed to match the text of the link. If the variable already has a string value when you load the passage, then the link text that matches the variable will be selected, instead of the first one.

If the last parameter is the word "end", then it will terminate the cycling link at the parameter before last. The containing that text will replace the link element altogether. New: Similarly, if the last parameter is the word "out", then it will disappear altogether after the final link text is clicked.

Usage examples:
* You look around, but only see <<cyclinglink "grass" "a flower" "a cloud" "the road">>. - This is a purely cosmetic, endlessly cycling link.
* You see a bowl containing <<cyclinglink "3 cookies" "2 cookies" "1 cookie" "a few crumbs" end>>. - This link changes to the words "a few crumbs" when you get to the end.
* You see a dial: <<cyclinglink $heat "off" "low" "high" "fearsome">>. - The $heat variable will be changed to "off" when the page loads (unless it was already set to "high" or "fearsome"), and then sets it to "low", "high" and "fearsome" as the player clicks the link.
* You see a fuel gauge: <<cyclinglink $fuel "100%" "50%" "10%" "0%" end>>.
* You see an air meter: <<cyclinglink $air "********" "******" "****" "**" out>>.

Example program 1 (cosmetic).
Example program 2 (mechanical).
Example program 3 (mechanical with CSS). - see below for CSS hooks.

Implementation details:
* For CSS users: the <a> tag has the class names "cyclingLink" and "internalLink".
* Each option is a <span> inside the <a> tag. Clicking it causes the next one down to have the class "cyclingLinkEnabled", and the others to have the class "cyclingLinkDisabled". New: on passage load, each option also has the class "cyclingLinkInit", which is removed as each is clicked.
* When you click, the "data-cycle" attribute of the <a> tag increases by 1 (wrapping around to 0 at the end). You could select this with CSS, I guess, using [data-cycle=1] or somesuch.

Version history:

1. 9-8-13 - Added 'cyclingLinkInit' class support.
2. 27-3-13 - Bugfixes, added "out" parameter.
3. 4-3-13 - Bugfix.
4. 27-2-13 - Added CSS hooks and the "end" parameter.
5. 26-2-13 - Added new variable-setting ability.
6. 16-2-13 - Fixed typo preventing it from working.
7. 29-1-13 - Initial.