random - jQuery show and hide does not work consistently -


i'm attempting make button display random element when clicked using show/hide. sets element hidden first stop duplicates, shown. doesn't show.

the fiddle clearer explanation: http://jsfiddle.net/qafqn/.

simplified code:

    this.uiselect = function(){     var length = $("#ui li").length;     var ran = math.floor(math.random()*length);         $('#ui li').hide();     $("#ui li:nth-child(" + ran + ")").show(); };      $(document).ready(function(){        $('#mangle').click(function(){         uiselect();     });  });

use :eq() instead of :nth-child(). have quite different meaning. former refers element's position in jquery collection, while latter refers position among dom siblings. these not same in situation.

consider following markup:

 div     > ul         > li 1         > li 2     > ul         > li 3         > li 4         > li 5

the query $('div li:eq(2)') return li 3 (indices zero-based), because third element in collection. on other hand, $('div li:nth-child(3)') (indices one-based here, why wrote 3 instead of 2) return li 5, because third element in group, among siblings.

you can save ugly string concatenation , duplicate dom lookups if use .eq() instead of :eq() , chaining this:

$("#ui li").hide().eq(ran).show();

jsfiddle demo


Comments

Post a Comment

Popular posts from this blog

linux - xterm copying to CLIPBOARD using copy-selection causes automatic updating of CLIPBOARD upon mouse selection -

i've tried various ways coerce xterm (versions 285 , 292) copy selection clipboard clipboard whenever press ctrl-shift-c. promising way far has been, in ~/.xresources, put this: xterm*vt100.translations: #override \ ctrl shift <keypress> c: copy-selection(clipboard) \n\ ctrl shift <keypress> v: insert-selection(clipboard) ctrl-shift-v works perfectly, copying has nuance... if restart xterm, highlighting text puts things in primary clipboard; expected, proper, default behavior. if hit ctrl-shift-c, copies current selection clipboard clipboard. the bug, however, if highlight text after first time pressed ctrl-shift-c, you'll see highlighting copies both primary and clipboard. cannot figure out how stop xterm updating clipboard upon selection... , doesn't make sense me in first place. i said, @ specific point in time, copy selection clipboard... yet starts updating automatically upon selection after doing once... anyone have workaround...
Read more

c++ - qgraphicsview horizontal scrolling always has a vertical delta -

Image
i've subclassed qgraphicsview custom canvas used in cad application. i've reimplemented qgraphicsview::wheelevent check keyboard modifiers control key and, if control key pressed, zoom. i'm trying implement horizontal scroll when user holds shift , uses wheel. the problem i'm having horizontal scrolling always scrolls 0.279. not huge problem, hugely annoying , points else being wrong. so, here questions: is right way implement horizontal scrolling? if not, is? how eliminate delta of 0.279? thanks in advance. code , sample output below void myview::zoom(int delta) { double factor = pow(1.2, delta/abs(delta)); this->scale(factor, factor); } void myview::scrollhorizontal(int level) { qpointf center = maptoscene(viewport()->rect().center()); qdebug() << "center: " << center.x() << ", " << center.y(); centeron(qpointf(center.x() - level, center.y())); } void myview::wheelevent(qwheeleve...
Read more