I am trying to generate QR code on my webpage with a data (id) I get from web service. I can not figure out how to insert a javascript variable as a part of <img> src parameter.
As you can see I can change the src using myFunction (AFTER button clicked). But I do not know how to insert id variable to the initial page load (to replace ID1_GOES_HERE at the end of img line).
Please help!
Here is a code:
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title>TEST</title>
</head>
<body>
<script>
var id1 = "41c0236f-ed21-4182-be3d-26513078f704";
function myFunction(){
var id2 = "41c0236f-ed21-4182-be3d-26513078f704";
document.getElementById('qr_img').src="http://chart.apis.google.com/chart?cht=qr&chs=300x300&chld=H|0&chl="+id2;
}
</script>
<img id="qr_img" src="http://chart.apis.google.com/chart?cht=qr&chs=300x300&chld=H|0&chl=ID1_GOES_HERE"/>
<button onclick="myFunction()">test</button>
</body>
</html>
Don't use a button click handler, just call the function from your script:
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title>TEST</title>
</head>
<body>
<script>
var id1 = "41c0236f-ed21-4182-be3d-26513078f704";
function myFunction(){
var id2 = "41c0236f-ed21-4182-be3d-26513078f704";
document.getElementById('qr_img').src = document.getElementById('qr_img').src + id2;
}
myFunction();
</script>
<img id="qr_img" src="http://chart.apis.google.com/chart?cht=qr&chs=300x300&chld=H|0&chl="/>
<button>test</button>
</body>
</html>
The click handler is used to capture the button click event, and do something at that time. That's not what you want, so remove the button click handler.
At the end of the <script> element, simply call myFunction() to do what it's intended for.
If you wanted to run the script after the entire document and all of its dependencies were loaded, you could do this:
<script>
var id1 = "41c0236f-ed21-4182-be3d-26513078f704";
function myFunction(){
var id2 = "41c0236f-ed21-4182-be3d-26513078f704";
document.getElementById('qr_img').src = document.getElementById('qr_img').src + id2;
}
document.onload = myFunction();
</script>
For this simple case, you probably don't actually need a function at all, and the body of myFunction can simply be placed inline, like so:
<script>
var id1 = "41c0236f-ed21-4182-be3d-26513078f704";
var id2 = "41c0236f-ed21-4182-be3d-26513078f704";
document.getElementById('qr_img').src = document.getElementById('qr_img').src + id2;
</script>
The function would be useful if you had more logic involved, and needed to organize (or modularize) it.
You could add this to your script below where you declared and set the id1 variable
function Window_OnLoad ()
{
document.getElementById("qr_img").src="http://chart.apis.google.com/chart?cht=qr&chs=300x300&chld=H|0&chl="+id1;
}
Related
The problem is this: inside my main page (parent.html) I have an iframe (child.html) and a script block. In that script block there is a array of integers and a function that adds elements to the list. In the iframe there is a new function that adds an element to the list of the main file (parent.html).
I would like to know if it is possible for the iframe (child.html) to access this function found in parent.html. Example:
parent.html
<html>
<head>
<title>Parent</title>
<script>
var parentList = [0];
var counter = 0;
function addValue(){
counter++;
parentList.push(counter);
console.log('parent', parentList);
}
</script>
</head>
<body>
<button onclick="addValue()">Add Value (Parent)</button>
<br />
<iframe src="child.html" allowfullscreen></iframe>
</body>
</html>
child.html
<html>
<head>
<title>Child</title>
</head>
<body>
<button onclick="addValueInternal()">Add Value Child</button>
<script>
var internalCount = 0;
function addValueInternal() {
internalCount++;
parentList.push(internalCount);
console.log('child', parentList);
}
</script>
</body>
</html>
The error:
child.html:12 Uncaught ReferenceError: parentList is not defined
at addValueInternal (child.html:12)
at HTMLButtonElement.onclick (child.html:6)
Yes. it is possible. Based on an example calling a function defined in the parent from an embedded iframe.
So in your case, you would have to reference the parent when accessing your array.
function addValueInternal() {
internalCount++;
parent.parentList.push(internalCount); // here we access the reference
console.log('child', parentList);
}
Be aware that you may encounter problems concerning the cross-origin policy afterwards.
There is a file name vicidial.php in vicidia file a value is assigned
var DiaLControl_auto_HTML = 'something'
I dont want to edit in this file but i want to edit this variable from other file so i created file_js.js but when i assigned var DiaLControl_auto_HTML = 'my_value' its only use first one eg. something i want to override my variable. how can i do this ?
<script src="file_js.js"></script>
in vicidial.php
var DiaLControl_auto_HTML = 'default value';
in file_js.js
var DiaLControl_auto_HTML = 'my_value';
In vicidial have:
<script>
var DiaLControl_auto_HTML = 'default value';
</script>
<script src="file_js.js"></script>
in file_js.js
window.addEventListener("load",function() {
window.DiaLControl_auto_HTML = 'my_value';
})
this is a workable code , try it. I hope it can help you.
main html
<!doctype html>
<html lang="fr">
<head>
<meta charset="utf-8">
<title>Test Var</title>
<script src="file_js.js"></script>
</head>
<body>
<br>
Value before : <span id="valueBefore"></span><br>
<br>
Value after : <span id="valueAfter"></span><br>
<br>
<script>
var DiaLControl_auto_HTML="default value";
// the function() wil be executed when your page is loaded
// better use readystate==complete, but it is a another problem...
window.addEventListener("load",function() {
// set var
DiaLControl_auto_HTML = 'my_value';
// show it in browser
document.getElementById('valueBefore').innerHTML=DiaLControl_auto_HTML;
// call method on file_js
myOwnFunction();
// show it in browser
document.getElementById('valueAfter').innerHTML=DiaLControl_auto_HTML;
})
</script>
</body>
</html>
file_js.js
// file_js.js FILE
function myOwnFunction () {
DiaLControl_auto_HTML="Value changed";
}
I'm new to programming and would need some help, why the document.write() didn't work and basically the page crashes... Can anyone help me?
<!DOCTYPE html>
<html>
<head>
</head>
<script type="text/javascript">
function showText() {
var x;
var counter;
if ( x === 0) {
counter = 0;
x = 1;
}
counter = counter + 1;
document.write("Times clicked: " + counter);
}
</script>
<body>
<script type="text/javascript">
showText();
</script>
<button onclick="showText();">Click Me!<button>
</body>
</html>
Avoid using document.write
Quoting from the MDN Developer Network documentation page:
Note: as document.write writes to the document stream, calling document.write on a closed (loaded) document automatically calls document.open which will clear the document.
So basically, your issue is using document.write after the page has loaded: this will result in deleting the entire content of the page and displaying that string.
Also, your code doesn't work because your count variable is declared inside the showText function, and you're trying to access it outside of it, running into an error.
Solution
To make your code work you should create another element, let's say a <p> element, and display the text inside of it. Here's an example of a correct page:
<!DOCTYPE html>
<html>
<head></head>
<body>
<button id="btn">Click me!</button>
<p id="txt">Times clicked: 0</p>
<script type="text/javascript">
function showText() {
count++;
text.textContent = "Times clicked: " + count;
}
var count = 0,
button = document.getElementById("btn"),
text = document.getElementById("txt");
button.addEventListener("click", showText);
</script>
</body>
</html>
Check out a live demo here.
I have written the following code to display an input with Javascript's alert( ... ) function.
My aim is to take a URL as input and open it in a new window. I concatenate it with 'http://' and then execute window.open().
However, I just get 'http://' in the URL name, even after concatenation, and not the complete URL. How can I fix this?
<html>
<head>
<meta content="text/html;charset=utf-8" http-equiv="Content-Type">
<meta content="utf-8" http-equiv="encoding">
<body onload="onload();">
<input type="text" name="enter" value="" id="url_id">
<input type="button" value="Submit" onclick="func();">
</body>
<script type="text/javascript">
var url;
function onload() {
url = document.getElementById("url_id").value;
}
function func(){
var var1 = "http://";
var var2 = url;
var res = var1.concat(var2);
alert(var2);
//window.open(res);
}
</script>
</head>
</html>
You shouldn't be calling it in onload(), only after the user has entered the url into the input field. Of course its an empty string, because you assign url to the value of #url_id before the user has a chance to enter anything when you place it in onload().
function func(){
var var1 = "http://";
url = document.getElementById("url_id").value;
var var2 = url;
var res = var1.concat(var2);
alert(var2);
//window.open(res);
}
Others have given solutions, and you already have accepted one. But none of them have told you what is wrong with your code.
Fristly, you have a body element inside your head element. This is invalid markup. Please correct it:
<html>
<head>
<!-- this is a script -->
<script type="text/javascript">
// javascript code
</script>
</head>
<body>
<!-- this is an inline script -->
<script type="text/javascript">
// javascript code
</script>
</body>
</html>
Secondly, you need to have an idea about the execution order of JavaScript inside browser windows. Consider this example:
<html>
<body onload="alert('onload')">
<p>Lorem Ipsum</p>
<script type="text/javascript" >
alert('inline');
</script>
</body>
</html>
Which alert do you thing will get executed first? See the JSFiddle.
So as you can see, inline JavaScript will be executed first, and then the browser will call whatever code is in <body onload=.
Also, onload function is called immediately after the page is loaded. And user has not entered anything when the function is executed. That is why you get null for url.
function func()
var url = document.getElementById("url_id").value;
var fullUrl = "http://".concat(url);
alert(fullUrl);
// or window.open(fullUrl);
}
You're not concatenating with a String but with an Object. Specifically an HTMLInputElement object.
If you want the url from the text input, you need to concatenate with url.value.
if its not concatenating, use:
var res = val1+val2.value;
I have a number of links, that when clicked on, passes a variable thru to another portion of the page.
Yet, for some reason, I can’t figure it out! What am I missing?
<head>
<script type="text/javascript">
function myFunction(a){
myid="Hi There!"+a;
return myid;
}
</script>
</head>
<body>
Click Me<br />
<script type="text/javascript">
document.write(myid);
</script>
</body>
You are getting a little mixed up here. Even though the function returns a value, it has nothing to return it to. Try this:
<head>
<script type="text/javascript">
function myFunction(a){
myid="Hi There!"+a;
document.getElementById("debug").innerHTML = myid;
}
</script>
</head>
<body>
Click Me<br />
<div id="debug"></div>
</body>
if you want to use it later you need to declare myid as a global variable. its scope is currently only within myFunction. also the document.write() function will only execute at runtime so you need to have another function the executes that with every click, or just combine the two.
When you click the link all that happens is that the myFunction() is called which returns the string. The line document.write(myid); is not executed anymore so nothing is visible.
<script>
// This is global
var myid = ''
myfunc = function(a){
myid = "Hi There!" + a;
alert(myid);
}
test_global = function(){
alert(myid);
}
</script>
Set MYID
<input type="button" onclick="test_global();" value="Test MYID" />
Here is a simple example of some similar stuff:
clickme or ClickMeAlso
<input id='other' type='text'/>
<script>
function myfunc(a) {
return a + " howdy";
};
</script>
You can see this in action here:http://jsfiddle.net/5Sbn2/