Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <blockquote> <p>(1) JavaScript does not have block statement scope; rather, it will be local to the code that the block resides within. </p> <p>(2) Javascript's declaration of variables in a function scope, meaning that <strong><em>variables declared in a function are available anywhere in that function, even before they are assigned a value</em></strong>.</p> <p>(3) Within the body of a function, a local variable takes precedence over a global variable with the same name. <strong>If you declare a local variable or function parameter with the same name as a global variable, you <em>effectively hide the global variable</em></strong>.</p> </blockquote> <p>you code is same as: (<em>read comment</em>)</p> <pre><code>&lt;script&gt; var a = 1; //global a = 1 function b() { a = 10; var a = 20; //local a = 20 } b(); alert(a); //global a = 1 &lt;/script&gt; </code></pre> <p>reference:<br> (1) <a href="http://docstore.mik.ua/orelly/webprog/jscript/ch04_03.htm" rel="nofollow"><em>JavaScript Variable Scope:</em></a><br> (2) <a href="http://thecomputersarewinning.com/post/a-dangerous-example-of-javascript-hoisting/" rel="nofollow"><em>A Dangerous Example of Javascript Hoisting</em></a><br> (3) <a href="https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Values,_variables,_and_literals#Variable_Scope" rel="nofollow"><em>Variable scope</em></a></p> <p>So in your code: </p> <pre><code>var a = 1; //global a = 1 function b() { a = 10; return; function a() {} //local } b(); alert(a); //global a = 1 </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POJavaScript 'hoisting'
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USGrijesh Chauhan
    1. USGrijesh Chauhan
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTDownMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COwhere you wrote "local a Undefined" - that's actually not true. function declarations are parsed before any content of the parent scope, so in this case when you assign a = 10, you are already overriding function a() {} with value 10. See Quentin's answer
      singulars
      1. PO
      1. USrochal
    2. CO@rochal No, please read this article [Javascript hoisting can be especially nefarious in loops](http://thecomputersarewinning.com/post/a-dangerous-example-of-javascript-hoisting/) Also check code on safari browser...let me know And Yes its `a=10` on most browser ..Actually Undefined behaviour not ERROR
      singulars
      1. PO
      1. USGrijesh Chauhan
    3. COread point 4. from Quentin's answer. At this point `a` already exists - it's a function, not an Undefined. How would Safari be different to i.e. Chrome..?
      singulars
      1. PO
      1. USrochal
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload