How do I access class variables from an event in Javascript?
I'm using the prototype javascript l开发者_StackOverflow中文版ibraries. My code is below. I've created a class and in that class I have created an event listener for one of the class methods. In that method I need to access both the attributes of the form element that triggers the event and the class properties. Currently, the code understands $(this).getValue() in the event because this is being assigned to the form element that triggered the event. How can I access the this.makingRequest and this.user properties from the event function? Can I pass them in as parameters somehow? If so, how? Nothing I've tried to this point works. Thanks for any help.
function AddressBookEntryObj(user, selectField)
{
this.selectField = selectField;
this.user = user;
this.makingRequest = false;
this.debugMode = false;
Event.observe(this.selectField, 'change', handleEvent);
}
//Prototype statements
AddressBookEntryObj.prototype.handleEvent = handleEvent;
//End prototype statements
function handleEvent()
{
try
{
if (!this.makingRequest)
{
this.makingRequest = true;
var ajax =
new Ajax.Request(
'/servlet/MyReallyCoolServlet',
{
method: 'get',
parameters: {
action: 'doGet',
whichFunc: 'MyReallyCoolFunction',
fieldValue: $(this).getValue(),
user: this.user
},
onCreate: handleAjaxCreate,
onComplete: handleChangeComplete
}
);
return true;
}
else
{
return false;
}
}
catch (ex)
{
alert("handleEvent Error: \r\n" + ex.toString());
}
}
Thanks!
Andrew
jsfiddle example
Take a look at this jsfiddle I made with your code. You needed to add "bind(this)" to your callback handler. Doing that will make "this" be your object and use "e.target" to access the html element.
_Michael
Firstly use:
AddressBookEntryObj.prototype.handleEvent = function()
{
}
Then this
inside handleEvent should point to AddressBookEntryObj
. To be sure it will work everywhere inside that function use something like:
var _this = this;
And then use _this
inside any event handlers.
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