It’s time to check how the mode of printing even and odd pages works.
To enable this mode, let’s set the mode variable to the 'alternate' mode.
To print even pages instead of odd ones, let’s change the start page from the first one to the second one.
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New project: driver development</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/use-for-loop">2. Managing the number of copies</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/print-all-pages">3. Learning the for loop</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/print-pages-fixed">4. Correcting the loop</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/print-reverse">5. Printing the pages in reverse order</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/print-odd-pages">6. Printing only odd pages</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/print-even-pages">7. Printing only even pages</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/all-modes-1">8. Printing driver: copy mode</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/all-modes-2">9. Printing driver: all pages</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/all-modes-3">10. Printing driver: pages in reverse order</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/all-modes-4">11. Print driver: even and odd pages</a></li><li class="main-nav__course-contents-item main-nav__course-contents-item--current"><a href="/courses/javascript-programming/loops/all-modes-5">12. Print driver: switching evens and odds</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/accumulation">13. Accumulation in the loop</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/conditions">14. Checks in loops</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/division">15. Searching for an even number</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/calc-toner-1">16. How much does printing cost?</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/calc-toner-2">17. Economy printing</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/calc-toner-3">18. Saving ink</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/summary-1">19. Summary of “Loops”. Part 1</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/for-challenge">20. Third program: “Protein shake!”</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/hello-while">21. It’s been a “while”</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/while-total">22. The while loop, summation</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/dart-machine-1">23. Another project: a dart machine</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/dart-machine-2">24. Dart machine: accumulating misses</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/dart-machine-3">25. Dart machine: defeat</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/dart-machine-5">26. Dart machine: final scoreboard</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/summary-2">27. Summary of “Loops”. Part 2</a></li><li class="main-nav__course-contents-item"><a href="/courses/javascript-programming/loops/while-challenge">28. 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fill="#EFA75B"/><path d="M31.963 50.968c-.197-.004-.358-.157-.372-.353-.018-.207.158-.378.364-.354 3.245-.26 3.505-2.156 3.608-2.25-.006-.19.183-.325.362-.26.193.01.35.16.363.354 0 .084 0 1.906 3.422 2 .192.008.348.16.362.353-.018.19-.172.34-.363.353-1.352.11-2.68-.4-3.61-1.386-.095-.096-.16-.22-.185-.353-.982 1.174-2.423 1.866-3.952 1.898z" fill="#151841"/><path d="M32.14 43.427c.186-.52 3.608.083 3.608.083s2.975-.688 3.422.084c-.05.288-.175.557-.363.78-.515-.056-1.037.004-1.525.178-.333.61-.488 1.304-.446 2-.222.394-.574.7-.995.864-.398-.112-.75-.354-.994-.688.047-.75-.146-1.496-.55-2.13-.27-.26-1.264.084-1.626-.083l-.53-1.088zm6.89.242c-.05.286-.175.556-.363.78-.503-.063-1.015-.012-1.497.148-.333.612-.487 1.305-.446 2-.222.394-.574.7-.995.864-.4-.112-.75-.354-.996-.688.053-.76-.14-1.515-.55-2.157-.268-.26-1.263.084-1.626-.084-.26-.23-.45-.53-.55-.864" fill="#CF4A27"/><path d="M35.748 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2.334.725-.13.837-1.46.93-2.13h.112c.937.492 1.647 1.33 1.98 2.334-.388.176-.793.31-1.21.4zm18.365-2.864c-1.104-.145-2.215-.232-3.33-.26-.546-.01-1.093.05-1.626.176-1.166.483-2.08 1.425-2.53 2.604l-.158.79 1.795.623c.558.153 1.132.24 1.71.26h.28c3.245-.177 4.137-3.72 4.137-3.72l.084-.353zm-1.264 1.86c-.54 1.394-2.882 1.646-2.966 1.646-.517-.02-1.03-.11-1.525-.26-.186-.085-.633-.26-1.08-.43.374-.966 1.117-1.746 2.065-2.165 0 .68.158 1.953.81 2.083.65.13.613-1.535.566-2.26.934.005 1.865.064 2.79.177-.11.316-.473.65-.66 1.17z" fill="#151841"/><path d="M19.26 39.27c.535 1.362 1.56 2.473 2.874 3.115.534.312 1.204-.07 1.207-.69.002-.285-.15-.55-.397-.695-.918-.46-1.65-1.222-2.073-2.158-.344-.957-1.972-.52-1.61.428zm29.45 3.125c1.083-.59 2.01-1.428 2.706-2.446.3-.556-.112-1.228-.743-1.21-.293.007-.56.17-.698.428-.568.776-1.306 1.412-2.158 1.86-.394.23-.517.742-.27 1.125.263.376.773.482 1.163.242z" fill="#EFA75B" stroke-width="13"/><path d="M16.025 32.436c1.525-1.386 2.427-4.408 2.79-6.835-.084.354 2.613.43 4.138-1.208 1.078-1.125.446-2-.186-3.375-1.71-3.552-4.585-6.323-7.384-8.918-.716-.69-1.44-2.428-2.706-2-.995.353-.93 3.2-.716 4.073 1.09 7.448 4.065 18.263 4.065 18.263zm37.372-.78c-1.704-1.826-2.822-4.12-3.208-6.585 0 .354-2.614.354-4.056-1.29-.995-1.127-.362-1.86.363-3.117 1.86-3.198 4.863-5.718 7.746-8.136.81-.604 1.627-1.47 2.79-.93.994.428.715 2.334.548 3.115-1.083 5.72-2.48 11.376-4.183 16.943z" fill="#FFF"/><path d="M53.564 20.422c-1.98.51-4.138 1.636-5.105 3.487-.43-2.196 1.645-4.65 3.393-5.832.333-.21.312-.703-.037-.886-.162-.085-.357-.076-.512.022-2.157 1.562-4.417 4.5-3.784 7.188.076.262.354.41.614.325l-.075.28c-.085.603.93.864.994.26.446-2.158 2.706-3.376 4.77-3.897.372-.076.522-.526.27-.81-.133-.15-.342-.204-.53-.138zM17.457 18.06c-.55-.354-.995.428-.55.865 1.433 1.004 3.182 3.05 3.395 4.956-.93-1.86-3.05-2.975-5.105-3.486-.386-.005-.633.41-.445.747.042.076.103.14.176.184 2.073.52 4.324 1.73 4.77 3.896.106.328.5.46.78.26.273.192.653.06.745-.26.735-2.66-1.6-5.728-3.766-7.16z" fill="#F1662A"/></svg></span><p class="course-loading-overlay__message"><b class="course-loading-overlay__message-title">Loading…</b><br><span class="course-loading-overlay__message-text">Everything will be ready in few seconds</span></p></div></div><div class="course-layout__sidebar course-theory"><div class="course-theory__inner course-theory__inner--left-stub"><button class="course-theory__close icon-close icon-close--light" type="button">Close</button><ul class="course-tabs course-tabs--non-interactive course-layout__theory-heading js--theory-tabs"><li class="course-tabs__item course-tabs__item--external course-tab course-tab--centered"><span class="course-tab__icon"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#icon-theory"></use></svg></span><span class="course-tab__title">Theory</span></li><li class="course-tabs__item course-tabs__item--internal course-tab course-tab--centered course-tab--active js--theory-tab__theory"><span class="course-tab__icon"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#icon-theory"></use></svg></span><span class="course-tab__title">Theory</span></li><li class="course-tabs__item course-tabs__item--internal course-tab course-tab--centered js--theory-tab__comments"><span class="course-tab__icon"><svg aria-hidden="true" style="width: 16px; height: 16px; fill: #2e2c9c;"><use xlink:href="/img/sprites/up.svg#comment"></use></svg></span><span class="course-tab__title">Comments</span></li></ul><section class="course-theory__content"><div class="js--theory-pane__theory course-theory__content-inner"><h1 class="course-theory__content-heading">Print driver: switching evens and odds</h1><div class="course-theory__content-text"><p>It’s time to check how the mode of printing even and odd pages works.</p><p>To enable this mode, let’s set the <code>mode</code> variable to the <code>'alternate'</code> mode.</p><p>To print even pages instead of odd ones, let’s change the start page from the first one to the second one.</p></div></div><div class="js--theory-pane__comments hidden course-theory__content-inner"><div class="course-theory__content-text"><h2 class="course-theory__content-heading">Comments</h2><div id="disqus_thread"></div><script>
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var disqus_config = function () {
this.page.url = "https://htmlacademy.org/courses/javascript-programming/loops/all-modes-5";
this.page.identifier = "task-76";
};
(function() { // DON'T EDIT BELOW THIS LINE
var d = document, s = d.createElement('script');
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</script><noscript>Please enable JavaScript to view the <a href="https://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript></div></div></section><div class="course-theory__controls"><button class="button button--close" type="button">To the task</button></div></div></div><div class="course-layout__column course-layout__column--left"><ul class="js--course-tabs course-tabs course-layout__course-tabs"><li class="course-tabs__item course-tab js--editor-tab course-tabs__item--limited course-tabs__item--limited-large course-tab--active" data-editor="js"><span class="course-tab__title course-tab__title--indent"><span class="course-tab__title-part course-tab__title-part--active">script.js</span></span></li></ul><div class="course-layout__editors"><div class="js--editor course-editor course-layout__editor" id="" data-tab="js" data-split=""><span class="course-editor__label"><span class="course-editor__label-item">JavaScript</span></span><div class="course-editor__item" id="js-editor">var mode = 'reverse'; // Printing driver mode
var pageNumber = 5; // Copied page number
var copyCount = 7; // Number of copies
var totalPages = 6; // Pages in the document
var startPage = 1; // Starting page
if (mode === 'pageCopy') {
for (var copies = 1; copies <= copyCount; copies++) {
muffin.print(pageNumber);
}
}
if (mode === 'document') {
for (var page = 1; page <= totalPages; page++) {
muffin.print(page);
}
}
if (mode === 'reverse') {
for (var reversePage = totalPages; reversePage >= 1; reversePage--) {
muffin.print(reversePage);
}
}
if (mode === 'alternate') {
for (var alternatePage = startPage; alternatePage <= totalPages; alternatePage += 2) {
muffin.print(alternatePage);
}
}
</div></div></div><div class="course-editor-controls"><button class="course-editor-controls__item course-editor-controls__item--answer" type="button">Show the answer</button></div><div class="js--feedback course-unhappy"><button class="js--feedback-btn course-unhappy__button" type="button"><span class="sr-only">Complain</span><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#unhappy"></use></svg></button><div class="js--feedback-modal course-unhappy__modal course-unhappy__modal--step-one"><form method="POST" action="/courses/javascript-programming/loops/all-modes-5/signal" class="course-unhappy__form form"><input type="hidden" name="csrf_name" value="csrf69aed4481bbe7"><input type="hidden" name="csrf_value" value="faa60c836e60bf73af454db67df35608"><p class="course-unhappy__text">What didn’t you like in this task?</p><div class="course-unhappy__slide"><div class="course-unhappy__wrap"><div class="course-unhappy__list"><label class="checkbox checkbox--small"><input class="checkbox__input" name="problems" value="1" type="checkbox"><span class="checkbox__text">The code check doesn’t work</span></label><label class="checkbox checkbox--small"><input class="checkbox__input" name="problems" value="2" type="checkbox"><span class="checkbox__text">The task is too difficult</span></label><label class="checkbox checkbox--small"><input class="checkbox__input" name="problems" value="3" type="checkbox"><span class="checkbox__text">The theory is hard to understand</span></label><label class="checkbox checkbox--small"><input class="js--feedback-other-checkbox checkbox__input" name="problems" value="0" type="checkbox"><span class="checkbox__text">Other (will write below)</span></label></div><div class="course-unhappy__message"><label class="sr-only" for="id-message">Другое (сейчас напишу)</label><textarea class="field field--area" id="id-message" name="message" placeholder="For example, a typo in the word «heading»"></textarea></div></div></div><button class="course-unhappy__control course-unhappy__control--prev" type="button"><span class="sr-only">Prev</span><svg aria-hidden="true"><use xlink:href="/img/sprites/landings.svg#arrow"></use></svg></button><button class="course-unhappy__control course-unhappy__control--next" type="button" disabled><span class="sr-only">Next</span><svg aria-hidden="true"><use xlink:href="/img/sprites/landings.svg#arrow"></use></svg></button><button class="js--submit-btn button" disabled>Submit</button></form><p class="course-unhappy__result hidden">Thanks! We’ll fix everything at once!</p></div></div></div><div class="course-layout__column course-layout__column--right"><span class="course-separator-control"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#icon-arrows-separator"></use></svg></span><div class="course-browser"><div class="course-browser__menu"><span class="course-browser__menu-item course-browser__address"><span class="course-browser__menu-item-inner">Console</span></span><button class="js--autorun course-browser__menu-item course-browser__menu-button course-browser__menu-button--text-with-icon course-browser__menu-button--autorun course-browser__menu-button--autorun-on" title="Autorun" type="button"><span class="course-browser__menu-item-inner"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#icon-autorun"></use></svg>
Autorun
</span></button><button class="course-browser__menu-item course-browser__menu-button course-browser__menu-button--expand" type="button"><svg xmlns="http://www.w3.org/2000/svg" width="11" height="11" viewBox="0 0 11 11"><path d="M1.375 5.125v4.5h4.5m3.75-3.75v-4.5h-4.5" fill="none" fill-rule="evenodd" stroke="currentColor"></path></svg></button></div><div class="course-browser__notification js--browser-change-heading hidden"><p class="course-browser__notification-text">The code has changed, click “Run” or turn autorun on.</p><button class="course-browser__notification-button course-browser__notification-button--play js--close" type="button"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#icon-play"></use></svg>
Run</button></div><div class="course-browser__content"><div class="console js--console"><h2 class="sr-only">Result</h2><div class="console__content js--console__content"></div></div></div><div class="course-goals js--goals"><div class="course-goals__heading"><span class="course-goals__heading-title"><span class="course-goals__count-label">Goals</span><span class="course-goals__count">completed</span></span><button class="course-goals__button course-goals__button--expand js--goals__expand" type="button"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#icon-collapse"></use></svg></button><a class="course-goals__button course-goals__button--next button button--green button--without-border hidden" href="/courses/javascript-programming/loops/accumulation" title="Accumulation in the loop"><svg aria-hidden="true"><use xlink:href="/img/sprites/courses.svg#arrow-white--mini"></use></svg></a></div><div class="course-goals__content"><p>Now let’s use the mode added in the previous task.</p><ol class="course-goals__list"><li class="course-goals__list-item">Change the value of the <code>mode</code> variable to <code>'alternate'</code><span class="mark">.</span></li><li class="course-goals__list-item">To print even pages, change the value of the <code>startPage</code> variable to <code>2</code><span class="mark">.</span></li></ol></div></div></div></div></article></div><div class="course-interface__overlay course-interface__overlay--active"></div></main><script
src="https://assets.htmlacademy.org/scripts/courses-spa/htmlacademy-task.v43.js"
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></script><script>HtmlacademyTask.setRoutes({task:'/courses/javascript-programming/loops/all-modes-5',check:'/courses/javascript-programming/loops/all-modes-5/check'});</script><script>HtmlacademyTask.setup(function(){this.setView(JsView),this.setRunner(JsRunner),this.setChecker(JsChecker,function(){this.setMatcher(function(e){e.goal("change.mode").code('var mode = "alternate"; "#builtin.anything"').goal("even.vs.odd").code('"#builtin.anything"; var startPage = 2; "#builtin.anything"')}),this.addGoal("change.mode"),this.addGoal("even.vs.odd")}),this.setAnswers([{goal:1,editor:"js",data:function(){this.tooltip("Enable the mode of printing even and odd pages").at(0,12).find("reverse").replace("alternate")}},{goal:2,editor:"js",data:function(){this.tooltip("Print even pages").at(4,16).find("1").replace("2")}}])});</script><footer class="page-footer page-footer--tiny"><div class="page-footer__inner"><p><a href="/docs/cookies">Cookies</a> ∙
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