I have the following function (onButtonClick) when the button is clicked only the first function works. All the included functions work if I only have one of them in the button function.
I have also tried the on button click function this way as well. Still does not work.
setProjectData() && getProjectData() && window.location.href='support_page.html';
Any ideas on what I may be missing?
<span class="profile_container_right">
<a onclick='onButtonClick()'; return true;"; ><img src="images/bSUPPORT.png"/></a>
</span>
<script>
/* on button click */
function onButtonClick(){
setProjectData();
getProjectData();
window.location.href='support_page.html';
}
function setProjectData() {
// --- set local storage project descriptions ---
vProjectName=‘The Project Name’;
localStorage.setItem('xProjectName', vProjectName);
return true;
}
function getProjectData() {
// --- get local storage project descriptions ---
vProjectName = localStorage.getItem('xProjectName');
alert('you entered the GET project data function ='+vProjectName);
return true;
}
</script>
First issue is the use of quotes in the onclick binding:
onclick='onButtonClick()'; return true;";
The correct syntax for onclick is onclick="yourFunctionCall();" for example:
onclick="onButtonClick(); return true;"
Second issue is your use of quotes in the setProjectData function:
vProjectName=‘The Project Name’;
Change to single quotes or double quotes:
vProjectName="The Project Name";
With these syntax issues fixed your code should execute as expected.
Side note use var to declare variables within a function to make them adhere to the scope of the function. Declaring a js variable without the var exposes the variable globally.
Related
I can't find out what is the problem with this JSFiddle.
HTML:
<input type="button" value="test" onclick="test()">
JavaScript:
function test(){alert("test");}
And when I click on button - nothing happened. The console says "test not defined"
I've read the JSFiddle documentation - there it says that JS code is added to <head> and HTML code is added to <body> (so this JS code is earlier than html and should work).
If you do not specify the wrap setting it defaults to "onLoad". This results with all JavaScript being wrapped in a function run after result has been loaded. All variables are local to this function thus unavailable in the global scope.
Change the wrapping setting to "no wrap" and it'll work:
http://jsfiddle.net/zalun/Yazpj/1/
I switched the framework to "No Library" as you don't use any.
The function is being defined inside a load handler and thus is in a different scope. As #ellisbben notes in the comments, you can fix this by explicitly defining it on the window object. Better, yet, change it to apply the handler to the object unobtrusively: http://jsfiddle.net/pUeue/
$('input[type=button]').click( function() {
alert("test");
});
Note applying the handler this way, instead of inline, keeps your HTML clean. I'm using jQuery, but you could do it with or without a framework or using a different framework, if you like.
There is another way, declare your function into a variable like this :
test = function() {
alert("test");
}
jsFiddle
Details
EDIT (based on the comments of #nnnnnn)
#nnnnnn :
why saying test = (without var) would fix it ?
When you define a function like this :
var test = function(){};
The function is defined locally, but when you define your function without var :
test = function(){};
test is defined on the window object which is at the top level scope.
why does this work?
Like #zalun say :
If you do not specify the wrap setting it defaults to "onLoad". This results with all JavaScript being wrapped in a function run after result has been loaded. All variables are local to this function thus unavailable in the global scope.
But if you use this syntax :
test = function(){};
You have an access to the function test because it's defined globally
References :
https://stackoverflow.com/a/338053/3083093
https://stackoverflow.com/a/5830423/3083093
Change wrap setting in the Frameworks & Extensions panel, to "No wrap-in <body>"
There is no problem with your code.Just choose the extension onLoad() from right side.
<script>
function test(){
alert("test");
}
</script>
<input type="button" value="test" onclick="test()">
Select OnDomready
HTML:
<input id="dButton" type="button" value="test"/>
JavaScript:
addEventListener('load', init, false);
function init()
{
oInput = document.getElementById('dButton');
oInput.onclick = test;
}
function test(){
alert("test");
}
I have a functionality that I had running in the
window.addEventListener('load', function() {
var variable_name_1 = localStorage.getItem('var_1');
...
}
and I would like to move the functionality such that it only runs when the user clicks a button, in here:
function maketempuser() {
...
}
I can get the function to call when I want. But the function utilizes tons of variables from the load function. Is there a clean way to "globalize" these variables? Or must I find some way to add all these variables in the html:
<button ... onclick='maketempuser(variable_name_1, variable_name_2, ...);' >
NOTE: the javascript will run the same file, I just don't want it to keep re-running every time the user reloads the page since there is an ajax mysql insert that occurs because this page is one in a line of pages that enables a user to register.
To not pollute the global scope with a lot of variables (which can be overridden by other apps), I recommend you create an object with an app specific name, maybe something like this
var myAppVar = {};
window.addEventListener('load', function() {
myAppVar.var_1 = localStorage.getItem('var_1');
...
}
Just define them in global scope:
var variable_name_1;
window.addEventListener('load', function() {
variable_name_1 = localStorage.getItem('var_1');
...
}
This, however, is not a particularly healthy technique, since it's prone to name collisions. Best thing to do is have a custom object (cO, or with your initials, something unlikely to be used by anything else) and use it as a placeholder for all your custom vars:
var cS = {
var_1:null // or some default value...
};
window.addEventListener('load', function() {
cS.var_1 = localStorage.getItem('var_1');
...
}
Since localStorage is already global just retrieve the values you need in your handler from there.
function maketempuser() {
var variable_name_1 = localStorage.getItem('var_1');
}
No need to add anything extra to the global scope at all.
So as you might know, Razor Syntax in ASP.NET MVC does not work in external JavaScript files.
My current solution is to put the Razor Syntax in a a global variable and set the value of that variable from the mvc view that is making use of that .js file.
JavaScript file:
function myFunc() {
alert(myValue);
}
MVC View file:
<script language="text/javascript">
myValue = #myValueFromModel;
</script>
I want to know how I can pass myValue directly as a parameter to the function ? I prefer to have explicit calling with param than relying on globals, however I'm not so keen on javascript.
How would I implement this with javascript parameters? Thanks!
Just have your function accept an argument and use that in the alert (or wherever).
external.js
function myFunc(value) {
alert(value);
}
someview.cshtml
<script>
myFunc(#myValueFromModel);
</script>
One thing to keep in mind though, is that if myValueFromModel is a string then it is going to come through as myFunc(hello) so you need to wrap that in quotes so it becomes myFunc('hello') like this
myFunc('#(myValueFromModel)');
Note the extra () used with razor. This helps the engine distinguish where the break between the razor code is so nothing odd happens. It can be useful when there are nested ( or " around.
edit
If this is going to be done multiple times, then some changes may need to take place in the JavaScript end of things. Mainly that the shown example doesn't properly depict the scenario. It will need to be modified. You may want to use a simple structure like this.
jsFiddle Demo
external.js
var myFunc= new function(){
var func = this,
myFunc = function(){
alert(func.value);
};
myFunc.set = function(value){
func.value = value;
}
return myFunc;
};
someview.cshtml
<script>
myFunc.set('#(myValueFromModel)');
myFunc();//can be called repeatedly now
</script>
I often find that JavaScript in the browser is typically conceptually tied to a specific element. If that's the case for you, you may want to associate the value with that element in your Razor code, and then use JavaScript to extract that value and use it in some way.
For example:
<div class="my-class" data-func-arg="#myValueFromModel"></div>
Static JavaScript:
$(function() {
$('.my-class').click(function() {
var arg = $(this).data('func-arg');
myFunc(arg);
});
});
Do you want to execute your function immediately? Or want to call the funcion with the parameter?
You could add a wrapper function with no parameter and inside call your function with the global var as a parameter. And when you need to call myFunc() you call it trough myFuncWrapper();
function myFuncWrapper(){
myFunc(myValue);
}
function myFunc(myParam){
//function code here;
}
I am new in HTML5 & trying to learn drag & drop feature.I have a JavaScript function for creating div element & attaching dragstart event to it.
var taskDefination = document.createElement("div");
taskDefination.className = "defaultButtonHolder";
taskDefination.setAttribute("draggable","true");
document.getElementById("toDo").getElementsByClassName('columnContent')[0].appendChild(taskDefination);
taskDefination.addEventListener('dragstart', dragStart, false);
}
Now I have a drop zone created as
<span class="columnWidth">
<div class ="columnHeader">Progress</div>
<div class ="columnContent" ondragenter ="dragDrop.dragEnter(event)"></div>
</span>
where the dragEnter function belongs to an external javascript file where it has been designed as a closure.I have checked network tab and this javascript file is perfectly loading.
var dragDrop = function(){
var _dragEnter = function(){
console.log("Dragged dropped");
}
return{
dragEnter:_dragEnter
}
}
Now the issue is whenever i am trying to drop the element in dropzone it is throwing an undefined not a function error. But ondropeneter event , if calling a function written in same HTML page it is perfectly executing.Why does it throwing an undefined not an function error though it is working fine function written in same HTML page?
Your closure isn't properly formed. As it stands, dragDrop is a function object returned from the function expression and as such doesn't have the code you want attached to it. Have a quick read of function expressions here:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/function
It looks like you're trying to use a closure to implement a module pattern. To do this, you need to rebuild your code like this:
var dragDrop = (function() {
var _dragEnter = function(){
console.log("Dragged dropped");
}
return {
dragEnter:_dragEnter
}
})();
The first set of brackets around the (function {}) make it a closure. The second set of brackets afterwards (function {})() execute it immediately. This means your module is returned to the var dragDrop and then you will be able to successfully call dragDrop.dragEnter.
Below is the code that I used for multiple java scripts on a single button. But only any one is working when I disable the second one. Please let me know: how do I change my code to make it to work fine?
function invoke(but)
{
if(but==0)
{
function move(){
document.getElementById('tgt1').value =
document.getElementById('Allocation').value;
document.getElementById('Allocation').value="";
document.getElementById("Send").disabled=true;
}document.myform.action="Alloc_Insert.do";
}
else if(but==1)
{
document.myform.action="";
}
else if(but==2){ document.myform.action="WL_Verif.do";}
else if(but==3){ document.myform.action="Add_Query.do";}
document.myform.submit();
}
And the html is as below:
<input type="Submit" value="Allocate" id="Send" name="submit" onClick="invoke(0);move();"/><br/>
change the name of the button to something else than "submit"
To explain what happens:
When you assign the name-attribute "submit" to the button(or any other form-element), this element will be accessible via
document.myform.submit
but there is also the build-in method of a form: submit(), you also may access it by using
document.myform.submit
What happens now when you call document.myform.submit()
I'll write the code a little bit different, and you will see trouble:
document.myform['submit']()
Instead of accessing the built-in method, the code points first to the form-element, and then tries to execute the method. But a form-element is not a method, it all ends up in an error and the rest of the script(including the call of move() ) will not get executed.
It's the same with "reset", you never should use the name of a built-in property/method of the form-element as name for form-elements.
notice the 'move' function is not declared outside the 'invoke' function.
Then;
either wrap them in a self invoking function:
onclick="(function(){ invoke(0);move(); })();"
or attach event handlers (preferred usually)
div.attachEventListener('click', function () { ... }); // DOM 3
div.attachEvent('click', function () { ... }); // IE
Your functions are declared in a weird way. You're defining move inside of invoke, which I don't think you want. If you want to have two functions, put move outside of invoke, like this:
function move(){
document.getElementById('tgt1').value =
document.getElementById('Allocation').value;
document.getElementById('Allocation').value="";
document.getElementById("Send").disabled=true;
}
function invoke(but)
{
if(but==0)
{
move();
document.myform.action="Alloc_Insert.do";
}
else if(but==1)
{
document.myform.action="";
}
else if(but==2){ document.myform.action="WL_Verif.do";}
else if(but==3){ document.myform.action="Add_Query.do";}
document.myform.submit();
}
A note: it's generally not a good idea to use onClick in your HTML -- it's better to put that in your JavaScript.
I think the problem is the scope of the move() function. Try defining move outside of invoke.
function invoke (but) {
if(but==0) {
document.myform.action="Alloc_Insert.do";
// I don't know if you meant to call move() here or not
}
else if (but==2) { document.myform.action="WL_Verif.do"; }
else if (but==3) { document.myform.action="Add_Query.do"; }
document.myform.submit();
}
function move(){
document.getElementById('tgt1').value =
document.getElementById('Allocation').value;
document.getElementById('Allocation').value="";
document.getElementById("Send").disabled=true;
}
Also, properly formatting your code will do wonders to the legibility of it.
NOTE: Firefox seems to be quite happy to execute the onClick="invoke(0);move();" even if move is defined inside invoke. Chrome however won't execute move because it can't find it. So be sure to test your script in multiple browsers as well.