Develop Reference

how to split the textarea into parts in javascript

I am trying to open the 5 urls inputted by the user in the textarea
But the array is not taking the url separately instead taking them altogether:
function loadUrls()
{
var myurl=new Array();
for(var i=0;i<5;i++)
{
myurl[i] = document.getElementById("urls").value.split('\n');
window.open(myurl[i]);
}
}

You only should need to split the text contents once. Then iterate over each item in that array. I think what you want is:
function loadUrls() {
var myurls = document.getElementById("urls").value.split('\n');
for(var i=0; i<myurls.length; i++) {
window.open(myurls[i]);
}
}

Here's a working example:
var input = document.getElementById('urls');
var button = document.getElementById('open');
button.addEventListener('click', function() {
var urls = input.value.split('\n');
urls.forEach(function(url){
window.open(url);
});
});
<button id="open">Open URLs</button>
<textarea id="urls"></textarea>
Note that nowadays browsers take extra steps to block popups. Look into developer console for errors.

There are a couple issues I see with this.
You are declaring a new Array and then adding values by iterating through 5 times. What happens if they put in more than 5? Or less?
split returns a list already of the split items. So if you have a String: this is a test, and split it by spaces it will return: [this, is, a, test]. There for you don't need to split the items and manually add them to a new list.
I would suggest doing something like:
var myUrls = document.getElementById("urls").value.split('\n');
for (var i = 0; i < myUrls.length; i++) {
window.open(myUrls[i]);
}
However, as others suggested, why not just use multiple inputs instead of a text area? It would be easier to work with and probably be more user friendly.

Basically:
document.getElementById("urls").value.split('\n');
returns an array with each line from textarea. To get the first line you must declare [0] after split the function because it will return the first item in Array, as split will be returning an Array with each line from textarea.
document.getElementById("urls").value.split('\n')[0];
Your function could simplify to:
function loadUrls(){
var MyURL = document.getElementById("urls").value.split('\n');//The lines
for(var i=0, Length = MyURL.length; Length > i; i++)
//Loop from 0 to length of URLs
window.open(
MyURL[i]//Open URL in array by current loop position (i)
)
}
Example:
line_1...
line_2...
... To:
["line_1","line_2"]

Create array of certain attribute from a list of elements using jQuery

Say I have some of divs.
<div data-id="1"></div>
<div data-id="2"></div>
<div data-id="3"></div>
<div data-id="4"></div>
Is there a way to get an array of the data-id attribute: ["1", "2", "3", "4"] without using .each?

You could use .map(): (example here)
var array = $('div[data-id]').map(function(){
return $(this).data('id');
}).get();
console.log(array);
Alternatively, using pure JS: (example here)
var elements = document.querySelectorAll('div[data-id]'),
array = [];
Array.prototype.forEach.call(elements, function(el){
array.push(parseInt(el.dataset.id, 10));
});
console.log(array);
...or using a regular for-loop: (example here)
var elements = document.querySelectorAll('div[data-id]'),
array = [],
i;
for (i = 0; i < elements.length; i += 1) {
array.push(parseInt(elements[i].dataset.id, 10));
}
console.log(array);

You could use a for loop and do it without JQuery even, in case you are looking for a more primitive solution, like:
var nodes = document.querySelectorAll('[data-id]');
for(var i=0;i<nodes.length;i++){
// do something here with nodes[i]
}
Or to optain an array directly from your query result you could also use Array.prototype.map.call:
var values = Array.prototype.map.call(nodes, function(e){ return e.dataset.id; });

var array=$('div[data-id]');//array will store all the div containing data-id in the order as it is appearing in your DOM.
so suppose you want to get 2nd div just do like this array[1].attr('id')

Selecting inside a DOM element

This is the html code
<div class="extra-sub-block sub-block-experience">
<h6 style="display:inline;" id="exp-pos-0" class="extra-sub-block-head sub-block-head-experience">CEO</h6>
</div>
<div class="extra-sub-block sub-block-experience">
<h6 style="display:inline;" id="exp-pos-1" class="extra-sub-block-head sub-block-head-experience">COO</h6>
</div>
There are several such similar structures. Now I try to extract the values from each block.
var temp=document.getElementsByClassName('sub-block-experience');
var result=$(temp[0]+"#exp-pos-0");
This throws an error. I followed selecting element inside another DOM
I also tried
var temp=document.getElementsByClassName('sub-block-experience');
var result=temp[0].find('h6');
This doesn't work as well. What am I doing wrong here. Help?

For extracting the values from all blocks, you can use .map() function as follows:
var results = $('.extra-sub-block-head').map(function(){
return $(this).text();
})
Demo
side note: Since id is unique in a document, you can directly access the element using id selector like var result= $("#exp-pos-0");instead of var result=$(temp[0]+"#exp-pos-0");

Try, var result=$(temp[0]).find('h6');
Even, in the documentation link that you gave in question, it shows that you should wrap your result from document.getElementById in $() to be applied with jQuery. What it does is, that it converts the native javascript object into a jquery object.
Demo

function testIt(){
var tags, index;
tags = document.getElementsByTagName('h6');
for (index = 0; index < inputs.length; ++index) {
//do something ...
}
}

If I am correct you are trying to get ceo and coo?.If that's the case then with jquery:
var x= $('.extra-sub-block h6');
//values are
$(x[O]).html();
$(x[1]).html();

You could also use plain javascript:
var result = document.querySelectorAll('.sub-block-experience h6');
Or if you like it separate:
var temp = document.querySelectorAll('.sub-block-experience');
var result = [];
for(var i = 0, elem; elem = temp[i]; i++) {
result = result.concat(elem.querySelectorAll('h6'));
}
But be aware of the browser compatability of querySelectorAll and querySelector.

Replace string of text javascript

Im trying to replace a string of text for another string of text here is my code plus js fiddle
HTML
<div class="label">Rating:</div>
<div class="data rating">****</div>
Javascript
var str=document.getElementsByClassName("data" ,"raiting").innerHTML;
var n=str.replace(/\*/g,"star");
document.getElementsByClassName("data", "raiting").innerHTML=n;
Demo
http://jsfiddle.net/sgGQz/1/

document.getElementsByClassName() method returns, as its name suggests, a collection (HTMLCollection) of elements, not a single one -even if there's just a single element with the given classname(s) in DOM.
You need to go through each of them in order to make such a replacement. For example:
var elements = document.getElementsByClassName("data rating");
for (var i = 0, l = elements.length; i < l; i++) {
elements[i].innerHTML = elements[i].innerHTML.replace(/\*/g, 'star');
}
JSFiddle.
Alternatively, if you know for sure that there should be only a single element, you can assign it directly:
var elementToAdjust = document.getElementsByClassName("data rating")[0];
// ...

If you only have one occurrence of the element this will work:
var str=document.getElementsByClassName("data rating")[0].innerHTML;
var n=str.replace(/\*/g,"star");
document.getElementsByClassName("data rating")[0].innerHTML=n;
If multiple data rating elements exist use:
var elems =document.getElementsByClassName("data rating");
for(var i = 0; i < elems.length; i++){
elems[i].innerHTML = elems[i].innerHTML.replace(/\*/g,"star");
}
Both method correct some flaws in the original code.
First, rating was misspelled in the argument passed to getElementsByClassName. Second, getElementsByClassName() uses class names delimited by spaces to select elements with multiple classes, instead of multiple arguments. Get elementsByClassName returns an array of elements which must be iterated through.
JS Fiddle: http://jsfiddle.net/sgGQz/5/

You need to check again for getElementsByClassName,It returns node-List, so you can do like this and You can loop through then after each element and set your value
var str=document.getElementsByClassName("data" ,"raiting")[0].innerHTML;
var n=str.replace(/\*/g,"star");
document.getElementsByClassName("data", "raiting")[0].innerHTML=n;
Here is the example as you have only one occurance

javascript - get all anchor tags and compare them to an array

I have been trying forever but it is just not working, how can I check the array of urls I got (document.getElementsByTagName('a').href;) to see if any of the websites are in another array?

getElementByTagName gives you a nodelist (an array of nodes).
var a = document.getElementsByTagName('a');
for (var idx= 0; idx < a.length; ++idx){
console.log(a[idx].href);
}
I really suggest that you use a frame work for this, like jquery. It makes your life so much easier.
Example with jquery:
$("a").each(function(){
console.log(this.href);
});

var linkcheck = (function(){
if(!Array.indexOf){
Array.prototype.indexOf = function(obj){
for(var i=0; i<this.length; i++){
if(this[i]===obj){
return i;
}
}
return -1;
}
}
var url_pages = [], anchor_nodes = []; // this is where you put the resulting urls
var anchors = document.links; // your anchor collection
var i = anchors.length;
while (i--){
var a = anchors[i];
anchor_nodes.push(a); // push the node object in case that needs to change
url_pages.push(a.href); // push the href attribute to the array of hrefs
}
return {
urlsOnPage: url_pages,
anchorTags: anchor_nodes,
checkDuplicateUrls: function(url_list){
var duplicates = []; // instantiate a blank array
var j = url_list.length;
while(j--){
var x = url_list[j];
if (url_pages.indexOf(x) > -1){ // check the index of each item in the array.
duplicates.push(x); // add it to the list of duplicate urls
}
}
return duplicates; // return the list of duplicates.
},
getAnchorsForUrl: function(url){
return anchor_nodes[url_pages.indexOf(url)];
}
}
})()
// to use it:
var result = linkcheck.checkDuplicateUrls(your_array_of_urls);
This is a fairly straight forward implementation of a pure JavaScript method for achieving what I believe the spec calls for. This also uses closures to give you access to the result set at any time, in case your list of urls changes over time and the new list needs to be checked. I also added the resulting anchor tags as an array, since we are iterating them anyway, so you can change their properties on the fly. And since it might be useful to have there is a convenience method for getting the anchor tag by passing the url (first one in the result set). Per the comments below, included snippet to create indexOf for IE8 and switched document.getElementsByTagName to document.links to get dynamic list of objects.

Using Jquery u can do some thing like this-
$('a').each(function(){
if( urls.indexOf(this.href) !- -1 )
alert('match found - ' + this.href );
})
urls is the your existing array you need to compare with.