javascript - Is there a way to 'bake' the variable? -
i'm creating dynamic scroll page, decided use wheel event detect user's scrolling. may know event has deltay parameter updates dynamically(several times 1 scroll). want script return true once deltay bigger 100. updates on , on again causing function shoot several times. there way 'bake'(be able change once) true value?
window.addeventlistener('wheel', func) function func(event){ if(event.deltay>100){ var p = document.createelement('p'); var text = document.createtextnode("you scrolled on 100"); p.appendchild(text); document.body.insertbefore(p, document.getelementsbytagname('p')[0]); } } <p>scroll page down \/ , keep scrolling</p>
you remove listener once element has been added. way function not continue fire.
window.addeventlistener('wheel', func) function func(event){ if(event.deltay>100){ var p = document.createelement('p'); var text = document.createtextnode("you scrolled on 100"); p.appendchild(text); document.body.insertbefore(p, document.getelementsbytagname('p')[0]); window.removeeventlistener('wheel',func); } } https://developer.mozilla.org/en-us/docs/web/api/eventtarget/removeeventlistener
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