javascript - Elements not added to DOM by generator function -


i have been pulling hair out trying make simple code work. should render input fields in given dom, doesn't. why not?

var elems = 10;  function generateelems() {      (var = 0; < elems; i++) {         document.getelementsbytagname("div")[0].appendchild(document.createelement('input'));     }      //clean     var obj = null;     var elems = null; }  generateelems();

working demo

you dealing javascript variable hoisting here. remove line var elems = null; , code should work.

it considered best practise in javascript declare variables @ top of function body.

read article more information on javascript hoisting.

as discussing best practises, it's worth making note appending elements in loops bad idea performance. should use createdocumentfragment instead append elements , dump dom. saves expensive document reflows , makes significant difference in performance. 

var elems = 10;  function generateelems() {      var d=document.createdocumentfragment();      (var = 0; < elems; i++) {         d.appendchild(document.createelement('input'));     }      document.getelementsbytagname('div')[0].appendchild(d);       //clean     //var obj = null;     //var elems = null;  ----> commented out line, causing problem.   }  generateelems();

Comments

Post a Comment

Popular posts from this blog

java.util.scanner - How to read and add only numbers to array from a text file -

i'm learning java , have question regarding reading file want read numbers file contains strings well. here example of file: 66.56 "3 java 3-43 5-42 2.1 1 and here coding: public class test { public static void main (string [] args){ if (0 < args.length) { file x = new file(args[0]); try{ scanner in = new scanner( new fileinputstream(x)); arraylist<double> test = new arraylist<>(); while(in.hasnext()){ if(in.hasnextdouble()){ double f=in.nextdouble(); test.add(f);} else {in.next();} } catch(ioexception e) { system.err.println("exception during reading: " + e); } } my problem add 66.56,2.1 , 1 doesn't add 3 after "3 or ignores 3-43 , 5-42 can tell me how skip strings , add doubles here? thanks all said 3 ie; "3, 3-43 , 4-42 strings either u read string , split , check number @ " , - or put in space between characters , integers. jvm after compilation tre...
Read more

rewrite - Trouble with Wordpress multiple custom querystrings -

i'm working on adding multiple querystring , doesn't seem work. i've found codes seems work others might i'm missing something. i want like: http://mydomain.com/board/?getyear=2013&getsometext2=sometext to http://mydomain.com/board/2013/sometext/ i added code below functions.php file. doesn't seem work should though. this works. echoing querystring gets both variable without problem. http://mydomain.com/board/2013/sometext/ but doesn't. tested querystring vis isset() seems nothing being set/get http://mydomain.com/board/2013/ function add_query_vars($vars) { $vars[] = "getyear"; $vars[] = "getsometext2"; return $vars; } add_filter('query_vars', 'add_query_vars'); function add_rewrite_rules($arules) { $anewrules = array('board/([^/]+)/([^/]+)/?$' => 'index.php?pagename=board&getyear=$matches[1]&getsometext2=$matches[2]'); $arules = $a...
Read more