Replacing inner HTML fails despite onload function - javascript

I rarely have to do any Javascript and I seem to fail doing the easiest tasks. I am trying to replace a string in two divs. The first div gets replaced, the second one is not found with the error message:
drawings.html:20 Uncaught TypeError: Cannot set property 'innerHTML' of null
However I tried the usual remedies of putting my code in an 'onload' function and putting the script at the end of the body tag. What else could possibly go wrong?
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<div id="cell1">test<div>
<div id="cell2">test<div>
<script>
window.onload = function() {
replace();
}
function replace() {
console.log("replace");
document.getElementById("cell1").innerHTML = "cell1";
document.getElementById("cell2").innerHTML = "cell2";
}
</script>
</body>
</html>

just close your divs elements.
<html>
<head>
</head>
<body>
<div id="cell1">test</div>
<div id="cell2">test</div>
<script>
window.onload = function() {
replace();
}
function replace() {
console.log("replace");
document.getElementById("cell1").innerHTML = "cell1";
document.getElementById("cell2").innerHTML = "cell2";
}
</script>
</body>
</html>

Related

How can I make a variable be the select Id in a getElement

How can I make a variable be the select Id in a getElement? When I tried it, it returned null. My code is shown below:
<html>
<head>
</head>
<body>
<p id = "test">hi</p>
<script>
var test = "test";
document.getElementById(test).innerHTML = "complete";
</script>
</body
</html>
That code seems to work just fine (with the exception of the unclosed body tag), here is a runnable version of the code, fixed:
<html>
<head>
</head>
<body>
<p id = "test">hi</p>
<script>
var test = "test";
document.getElementById(test).innerHTML = "complete";
</script>
</body>
</html>
Remember, the js code is going to happen almost immediately, so you won't be able to see the "hi" part. If you want it to change after like 1 second, use this:
<html>
<head>
</head>
<body>
<p id = "test">hi</p>
<script>
var test = "test";
setTimeout(function () {
document.getElementById(test).innerHTML = "complete";
}, 1000);
</script>
</body>
</html>
All I changed in that, is put the document.getElementById() into a setTimeout
Hope this helped.

Javascript immediate function call from external function

I am trying to call the immediate function defined in test1.js on click of the button defined under html file. It always throws error "test is undefined". I am little bit aware that being a immediate function, it calls immediately, and so it returns the "undefined error". But is there any way I can call the immediate function (access methods, properties, etc.) on click of the button?
Thank you in advance.
//test1.js
var test = (function(){
alert(window);
var tmp = 'hello';
}());
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<script type="text/javascript" src="test1.js"></script>
<input type="button" id="btn1" value="ClickMe!" />
<script type="text/javascript">
var btn = document.getElementById("btn1");
btn.addEventListener("click",fun1,false);
function fun1(){
alert(test.tmp);
}
</script>
</body>
</html>
You have to modify your code so that the IIFE returns an object with a tmp property. Such as
var test = (function(){
alert(window);
var tmp = 'hello';
return {tmp:tmp};
}());
You need to explicitly return an object containing any data you want made available after you run the IIFE. (Just add the return as I did to the snippet below).
//test1.js
var test = (function(){
alert(window);
// you need to return any values you want accessible
return {
tmp: "hello"
}
}());
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<script type="text/javascript" src="test1.js"></script>
<input type="button" id="btn1" value="ClickMe!" />
<script type="text/javascript">
var btn = document.getElementById("btn1");
btn.addEventListener("click",fun1,false);
function fun1(){
alert(test.tmp);
}
</script>
</body>
</html>

not able to load contents in div using javascript

this is shan and i'm a javascript noob and i'm trying to work qa code as an example here. i'm trying to load a small javascript content to a div element but it is not working any help would be great and here is the code.
<html>
<head>
<title>
using d for statement
</title>
<script>
function displaytext () {
var loopindex=0;
var sum=0;
for (var loopindex=1; loopindex <=100; loopindex++) {
sum +=loopindex;
};
document.getElementById('targetdiv').innerhtml="adding 1 to 100 gives "+sum;
}
</script>
</head>
<body>
<div id="targetdiv">
</div>
</body>
</html>
You need to call the function. It's also a good idea to wait until the window is loaded (or you can use some more advanced JS to detect the DOM ready state.):
<html>
<head>
<title>
using d for statement
</title>
<script>
function displaytext() {
var loopindex=0;
var sum=0;
for (var loopindex=1; loopindex <=100; loopindex++) {
sum +=loopindex;
};
document.getElementById('targetdiv').innerHTML = "adding 1 to 100 gives "+sum;
}
window.onload = function(){
displaytext();
}
</script>
</head>
<body>
<div id="targetdiv">
</div>
</body>
</html>
3 problems:
You never actually call the function. It is only declared.
The property is innerHTML not innerhtml. Javascript is case-sensitive.
The script is above an element is is referencing. As scripts are executed as they are found (page construction is paused during execution) the element you are referring to is never found.
Also you declare the loopindex variable twice, which i think will cause a syntax error on ES5 strict.
<html>
<head>
<title>
using d for statement
</title>
</head>
<body>
<div id="targetdiv">
</div>
</body>
<script>
function displaytext () {
var sum=0;
for (var loopindex=1; loopindex <=100; loopindex++) {
sum +=loopindex;
};
document.getElementById('targetdiv').innerHTML="adding 1 to 100 gives "+sum;
}
displaytext();
</script>
</html>

Why does the browser modify the ID of an HTML element that contains &#x?

Say I've got this HTML page:
<html>
<head>
<script type="text/javascript">
function echoValue(){
var e = document.getElementById("/path/$whatever");
if(e) {
alert(e.innerHTML);
}
else {
alert("not found\n");
}
}
</script>
</head>
<body>
<p id="/path/$whatever">The Value</p>
<button onclick="echoValue()">Tell me</button>
</body>
</html>
I would assume that the browser treats the ID-string /path/$whatever as simple string. Actually, it converts the $ to it's rendered representation ($).
The javascript code however uses the literal string $ to search for the element. So, the call document.getElementById fails and I never get hands on the value of the paragraph.
Is there a way to force the browser into using the given ID string literally?
Edit:
Of course I know that I don't have to escape the $. But the web page gets generated and the generator does the escaping. So, I have to cope with what I've got.
In the <p id="...">, the $ sequence is interpreted as $, because it appears in an attribute and is treated as an HTML entity. Same goes for all other element attributes.
In the <script> element, HTML entities are not interpreted at all, so it shows up literally.
You could try decoding the javascript text without jQuery:
<html>
<head>
<script type="text/javascript">
function decodeEntity(text){
text = text.replace(/<(.*?)>/g,''); // strip out all HTML tags, to prevent possible XSS
var div = document.createElement('div');
div.innerHTML = text;
return div.textContent?div.textContent:div.innerText;
}
function echoValue(){
var e = document.getElementById(decodeEntity("/path/$whatever"));
if(e) {
alert(e.innerHTML);
}
else {
alert("not found\n");
}
}
</script>
</head>
<body>
<p id="/path/$whatever">The Value</p>
<button onclick="echoValue()">Tell me</button>
</body>
</html>
JSFiddle: http://jsfiddle.net/phTkC/
I'd suggest you to decode the HTML entity in your javascript code:
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script type="text/javascript">
function echoValue(){
var decoded_string = $('<div />').html("/path/$whatever").text();
var e = document.getElementById(decoded_string);
if(e) {
alert(e.innerHTML);
}
else {
alert("not found\n");
}
}
</script>
</head>
<body>
<p id="/path/$whatever">The Value</p>
<button onclick="echoValue()">Tell me</button>
</body>
</html>

javascript error with label

I have a function as follows:
function textNext(element, num) {
document.getElementById("lblContent").innerHTML = "hello";
}
However, the text of the lblContent label won't change when the function is called.
What am I doing wrong?
btw : lblContent is of type asp:Label
Since lblControl is a server side ASP.NET control, you will need to use the control ClientID property in order to use it in javascript:
function textNext(element, num) {
document.getElementById(<"%=lblContent.ClientID%>").innerHTML = "hello";
}
Check the console in your browser for errors. I tried to reproduce your problem in a standard HTML/Javascript environment.
This works for me.
<html>
<head>
<title>Test</title>
<head>
<body>
<div id="lblContent">Previous text</div>
Change text
<script type="text/javascript">
function textNext() {
document.getElementById("lblContent").innerHTML = "Next text";
}
</script>
</body>
</html>

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