What is the call flow for this window.onload scenario in javascript -

-

index.html

<!doctype html> <html> <head>     <title></title>     <script src="script1.js"></script>     <script src="script2.js"></script> </head> <body>  </body> </html>

script1.js

var main; window.onload = main;

script2.js

function main() {     alert("foo"); }

if throw breakpoint @ var main; , step through code in webstorm, appears to:

  1. load script1.js.
  2. load script2.js.
  3. call main().

however doesn't execute statement alert("foo") in function. explain what's going on in more detail?

  • note: realize should avoid using onload.
  • note: realize re-order scripts , show alert.
  • note: if omit statement var main;, step 3 above not occur.

bonus: in webstorm, shows value of window.onload field null , value of main void. difference between value of null , void?

because main empty variable @ point in script 1. window.onload set undefined. window.onload expects callback function so...

var main = function() { my_main_function() }

Comments

Post a Comment

Popular posts from this blog

delphi - How to convert bitmaps to video? -

-
Image
my application creates images fractals , love feeling of 'flying' around fractal. once saved 2000 bitmaps file , created avi using premiere. experience rather frustrating though succeeded in creating movie. spectacular. of course want create video application. don't care niftyness of codec, compression or whatever. want have video can replay on systems. in past have tried never succeeded. triggered question alas not ffmpeg running. update i decided adapt question , put bounty it. have seen several solutions attractive (because it's simple) seems me taviwrite. tried taviwriter did not succeed. in procedure taviwriter.write; function call around line 370 avierr := avisavev(s, // pchar(filename), nil, // file handler nil, // callback nstreams, // number of streams streams, compoptions); // compress options
Read more

jasper reports - Fixed header in Excel using JasperReports -

-
how can create excel report fixed header using japserreports? mean need header fixed when scroll excel file. this possible adding couple properties in jrxml file each report. take @ advanced excel features freeze panes. if wanted freeze after first column header (down left side basically) this: <statictext> <reportelement style="sans_bold" mode="opaque" x="0" y="60" width="104" height="20" forecolor="#ffffff" backcolor="#666666"> <property name="net.sf.jasperreports.export.xls.auto.filter" value="start"/> <property name="net.sf.jasperreports.export.xls.column.width" value="110"/> <property name="net.sf.jasperreports.export.xls.freeze.column.edge" value="left"/> </reportelement> &
Read more

python - ('The SQL contains 0 parameter markers, but 50 parameters were supplied', 'HY000') or TypeError: 'tuple' object is not callable -

-
import pyodbc,nltk,array cnxn = pyodbc.connect('driver={mysql odbc 5.1 driver};server=127.0.0.1;port=3306;database=information_schema;user=root; password=1234;option=3;') cursor = cnxn.cursor() cursor.execute("use collegedatabase ;") cursor.execute("select * sampledata ; ") cnxn.commit() s=[] j=[] x=[] words = [] w = [] sfq = [] pos=[] entry in cursor: s.append(entry.injury_type),j.append(entry.injury_desc) nltk.tokenize import punktwordtokenizer nltk.corpus import stopwords tokenizer = punktwordtokenizer() english_stops = set(stopwords.words('english')) in range(0,26): # filter stop words tokenizer.tokenize(j[i]) w.append([word word in tokenizer.tokenize(j[i]) if word not in english_stops]) in range(0 , 26):#converting tokenzied text ito string sfq.append(" ".join(w[a])) replacers import regexpreplacer replacer = regexpreplacer() in range (0,26):#pos tagging replacer.repl
Read more