Javascript – jQuery’s .click – pass parameters to user function

functionjavascriptjqueryparameter-passing

I am trying to call a function with parameters using jQuery's .click, but I can't get it to work.

This is how I want it to work:

$('.leadtoscore').click(add_event('shot'));

which calls

function add_event(event) {
    blah blah blah }

It works if I don't use parameters, like this:

$('.leadtoscore').click(add_event);
function add_event() {
    blah blah blah }

But I need to be able to pass a parameter through to my add_event function.

How can I do this specific thing?

I know I can use .click(function() { blah }, but I call the add_event function from multiple places and want to do it this way.

Best Answer

For thoroughness, I came across another solution which was part of the functionality introduced in version 1.4.3 of the jQuery click event handler.

It allows you to pass a data map to the event object that automatically gets fed back to the event handler function by jQuery as the first parameter. The data map would be handed to the .click() function as the first parameter, followed by the event handler function.

Here's some code to illustrate what I mean:

// say your selector and click handler looks something like this...
$("some selector").click({param1: "Hello", param2: "World"}, cool_function);

// in your function, just grab the event object and go crazy...
function cool_function(event){
    alert(event.data.param1);
    alert(event.data.param2);
}

I know it's late in the game for this question, but the previous answers led me to this solution, so I hope it helps someone sometime!

Related Solutions

Javascript – n “exists” function for jQuery

In JavaScript, everything is 'truthy' or 'falsy', and for numbers 0 means false, everything else true. So you could write:

if ($(selector).length)

You don't need that >0 part.

Python – What does ** (double star/asterisk) and * (star/asterisk) do for parameters

The *args and **kwargs is a common idiom to allow arbitrary number of arguments to functions as described in the section more on defining functions in the Python documentation.

The *args will give you all function parameters as a tuple:

def foo(*args):
    for a in args:
        print(a)        

foo(1)
# 1

foo(1,2,3)
# 1
# 2
# 3

The **kwargs will give you all keyword arguments except for those corresponding to a formal parameter as a dictionary.

def bar(**kwargs):
    for a in kwargs:
        print(a, kwargs[a])  

bar(name='one', age=27)
# name one
# age 27

Both idioms can be mixed with normal arguments to allow a set of fixed and some variable arguments:

def foo(kind, *args, **kwargs):
   pass

It is also possible to use this the other way around:

def foo(a, b, c):
    print(a, b, c)

obj = {'b':10, 'c':'lee'}

foo(100,**obj)
# 100 10 lee

Another usage of the *l idiom is to unpack argument lists when calling a function.

def foo(bar, lee):
    print(bar, lee)

l = [1,2]

foo(*l)
# 1 2

In Python 3 it is possible to use *l on the left side of an assignment (Extended Iterable Unpacking), though it gives a list instead of a tuple in this context:

first, *rest = [1,2,3,4]
first, *l, last = [1,2,3,4]

Also Python 3 adds new semantic (refer PEP 3102):

def func(arg1, arg2, arg3, *, kwarg1, kwarg2):
    pass

Such function accepts only 3 positional arguments, and everything after * can only be passed as keyword arguments.

Note:

A Python dict, semantically used for keyword argument passing, are arbitrarily ordered. However, in Python 3.6, keyword arguments are guaranteed to remember insertion order.
"The order of elements in **kwargs now corresponds to the order in which keyword arguments were passed to the function." - What’s New In Python 3.6
In fact, all dicts in CPython 3.6 will remember insertion order as an implementation detail, this becomes standard in Python 3.7.

Best Answer

Related Solutions

Javascript – n “exists” function for jQuery

Python – What does ** (double star/asterisk) and * (star/asterisk) do for parameters

Note:

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