CODEWITHSUNDEEP
javascriptjquery
Phillip Senn
Phillip Senn

Reputation: 47605

How to keep a value in JavaScript

After doing an async $.ajax call, I need to highlight the table cell that was updated.
Right now I'm using $td in the global name space, which of course is a wrong idea.

Q: How do I keep the value of $td when the jqXHR is called back? I think the answer has to do with closure, but I don't know.

var UpdateSort = function(ID,Sort){
    var jqXHR = $.ajax('Remote/Ajax.cfc', {
        data: {
        method:'UpdateSort'
        ,returnformat:'json'
        ,paramID:ID
        ,paramSort:Sort
    }
});
jqXHR.success(function(result){
    if (result.MSG == '') {
        $td.addClass('success');
    } else {
        $td.addClass('err');
    };
});

Upvotes: 1

Views: 294

Answers (3)

Wayne
Wayne

Reputation: 60414

A closure would solve your problem. Give UpdateSort a reference to your td and define your success function there:

var UpdateSort = function(ID,Sort, td){
    var jqXHR = $.ajax('Remote/Ajax.cfc', {
        data: {
        method:'UpdateSort'
        ,returnformat:'json'
        ,paramID:ID
        ,paramSort:Sort
    }
    jqXHR.success(function(result){
        if (result.MSG == '') {
            td.addClass('success');
        } else {
            td.addClass('err');
        };
    });    
});

The value of td will be available to the function given to jqXHR.success after UpdateSort returns because it is in that function's lexical scope.

Upvotes: 2

user657496
user657496

Reputation:

add 

var that;

to the top of your javascript file. At the end of the succes function add:

this.td = $td;
that = this;

This will store your td file in a global variable 'that' which you can use when it's called back. Take a look at this extremely useful document about variables : http://javascript.crockford.com/private.html

Upvotes: 1

Marcel Jackwerth
Marcel Jackwerth

Reputation: 54762

Just add it as an argument to your function.

var UpdateSort = function(ID,Sort,td){
    var jqXHR = $.ajax('Remote/Ajax.cfc', {
        data: {
        method:'UpdateSort'
          ,returnformat:'json'
          ,paramID:ID
          ,paramSort:Sort
        }
    }).success(function(result) {
      if (result.MSG == '') {
        td.addClass('success');
      } else {
        td.addClass('err');
      }
    });
});

Upvotes: 2

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