I want to write the following code by using functions:
<!DOCTYPE html>
<html>
<head>
<title> Test Java Script</title>
</head>
<body>
<button onclick=this.innerHTML=Date();> The Time Is: ? </button>
</body>
</html>
So I created a function and pass "this" as parameter, but it doesn't work:
<!DOCTYPE html>
<html>
<head>
<title> Test Java Script</title>
</head>
<body>
<button onclick=setTime(this)> The Time Is: ? </button>
</body>
<script type="text/javascript">
function setTime(Object b) {
b.innerHTML=Date();
}
</script>
</html>
What am I doing wrong ?
Try this:
<!DOCTYPE html>
<html>
<head>
<title> Test Java Script</title>
<script type="text/javascript">
function setTime(b) {
b.innerHTML=Date();
}
</script>
</head>
<body>
<button onclick="setTime(this);"> The Time Is: ? </button>
</body>
</html>
Add quotes to onclick.
Remove "Object" from function declaration.
Click the button.
Just remove the Object type from your function parameter and you're golden:
function setTime(b) {
b.innerHTML=Date();
}
As Katana314 mentioned in their comment, JavaScript doesn't use explicit types.
Here's a fiddle: http://jsfiddle.net/3cyj5916/
Related
Does flutter(Dart) have a function similar to js bind?
I wanted to do something similar in flutter.
like:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js">
</script>
<script>
function handlerName(e)
{
alert(e.data.msg);
}
$(document).ready(function(){
$("p").bind("click", {msg: "chicked!"}, handlerName)
});
</script>
</head>
<body>
<p>click me！</p>
</body>
</html>
There is nothing like bind in Dart
but this might do what you want as well:
onReady.listen((e) => handlerName(e, msg: 'clicked'))
I was learning javascript and experimenting with mouse events. In this code I am trying to manipulate the element when I put the mouse over it with the help of an alert box. However the problem is that the alert box is shown even when the mouse is not over the element.
<!DOCTYPE html>
<html>
<head>
<title>testing</title>
</head>
<body>
<a>dasdasd</a>
<p id="k">as</p>
<script type="text/javascript">
document.getElementById("k").onmouseover=alert('Hello');
</script>
</body>
</html>
The property onmouseover expect that you assing a function to it, instead you are assigning the evaluation of an expression, in this case: alert("hello"). So when the document loads, it evaluate that expression and the alert is shown, then a null value is assigned to the onmouseover property, that is the reason the alert only shows once.
For your goal, you can use an anonymous function to wrap the alert and assing it to the property. Check the next example:
<!DOCTYPE html>
<html>
<head>
<title>testing</title>
</head>
<body>
<a>dasdasd</a>
<p id="k" style="border: 1px solid red">as</p>
<script type="text/javascript">
document.getElementById("k").onmouseover = function() {alert('Hello')};
</script>
</body>
</html>
You need to put it in a function like so.
<!DOCTYPE html>
<html>
<head>
<title>testing</title>
</head>
<body>
<a>dasdasd</a>
<p id="k">as</p>
<script type="text/javascript">
document.getElementById("k").onmouseover = function(){alert('Hello')};
</script>
</body>
</html>
try to add onmouseover="mouseover()" in <p>
function mouseover() {
alert('Hello');
}
<!DOCTYPE html>
<html>
<head>
<title>testing</title>
</head>
<body>
<a>dasdasd</a>
<p id="k" onmouseover="mouseover()">as</p>
<script type="text/javascript">
function mouseover() {
alert('Hello');
}
</script>
</body>
</html>
The issue is, the () after the alert function causes the function invocation on page load and you see the alert. Call the function inside of an anonymous function which will ensure that the function will be called only when the event (onmouseover) is fired:
document.getElementById("k").onmouseover = function(){alert('Hello')};
<a>dasdasd</a>
<p id="k">as</p>
Try this (with JQuery):
$(document).ready(function(){
$("p").mouseover(function(){
alert("Hello");
});
});
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
</head>
<body>
<p>Move the mouse pointer over this paragraph.</p>
</body>
</html>
I have the following code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<button onclick="this.innerHTML=Date()">The time is?</button>
</body>
</html>
This is working fine.
But if I try to do the same thing by creating a separate JavaScript function, the code is not working.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<button onclick=displayDate()>The time is?</button>
<script>
function displayDate(){
this.innerHTML=Date();
}
</script>
</body>
</html>
What is the reason for this?
Your this isn't refer to the button itself, when it is in the function scope. You can achieve to the desired result with many approaches.
1) You can pass this to the function as a parameter
function displayDate(context){
context.innerHTML = Date();
}
<button onclick="displayDate(this)">The time is?</button>
2) Using explicit bindings, like call or apply
function displayDate(){
this.innerHTML = Date();
}
<button onclick="displayDate.call(this)">The time is?</button>
You can try to do something like this
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<button id="test" onclick=displayDate()>The time is?</button>
<script>
function displayDate(){
document.getElementById("test").innerHTML=Date();
}
</script>
</body>
</html>
What is diffrent between these syntax please Explain in details?
$(document).on("click", "#index1", function() {
$(p).hide();
});
$("#index2").on("click", "#index1", function() {
$(p).hide();
});
$("#index1").on("click", function() {
$(p).hide();
});
In first case you add click listener to "document", but it be executed only if you click at "#index1".
In second - you add listener to "index2" and it will be executed only if you click at "#index1" located inside of "#index2".
In the third case you just add listener to "index1"
Lets imagine a webpage at first.
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<button id='index1'>click me</button>
</body>
</html>
This will work
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<button id='index1'>click me</button>
<script type="text/javascript">
$("#index1").on("click", function () {
$(p).hide();
});
</script>
</body>
</html>
This won't work, because the element did not exist while the script was executed.
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
$("#index1").on("click", function () {
$(p).hide();
});
</script>
<button id='index1'>click me</button>
</body>
</html>
But with a workaround, it would
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<script type="text/javascript">
$(document).on("click", "#index1", function() {
$(p).hide();
});
</script>
<button id='index1'>click me</button>
</body>
</html>
This says whenever a click event is fired on the document check if the click was fired on #index1 element. So even if, the element did not exist the callback, is attached to the document node. Now whenever a click is fired on the document it will check if it originated from #index1
How can I pass argument to function redirect in JavaScript
Here is my code:
<script type="text/javascript">
<!--
function redirectlink(text){
window.location = "index.php?keyName="+ text;
}
//-->
</script>
<form>
<button type="button" id="butt_1" onclick="redirectlink(KEY_POWER)"> 1 </button>
Thank you in advance.
This can be done either by using getElementById and addEventListener
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<button id="foo">Click</button>
<script type="text/javascript">
document.getElementById("foo").addEventListener("click", function(){
window.location.replace("http://stackoverflow.com/q/36933820/5526354")
})
</script>
</body>
</html>
either onclick
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<button id="foo" onclick="action()">Click</button>
<script type="text/javascript">
function action(){
window.location.replace("http://stackoverflow.com/q/36933820/5526354")
}
</script>
</body>
</html>
Using onclick is deprecated.
With just only JavaScript (without jQuery / Angular etc.) you can use addEventListener on click event.
for example:
var btn = document.getElementById('butt_1');
btn.addEventListener('click', function(e) {
// your code
});
In this function you can for example get value/txt from this button element and something else which you want.