Why isn't this ajax post working correctly?

The function below makes an AJAX post. makepostrequest is just a standard ajax post request function I wrote that I have omitted since it's not the source of the problem. The function below does not send 'widgets'.

function widgets_positions(){
    var widgets = '';
    var col_1 = document.getElementById('col_1');
    var col_2 = document.getElementById('col_2');
    var col_3 = document.getElementById('col_3');
    for(i = 0; i < col_1.childNodes.length; i++) {
        var str1 = col_1.childNodes[i].className;
        if(str1 && str1.match('widget')) widgets+='&c[1]['+i+']='+col_1.childNodes[i].id;
    }

makePOSTRequest('/ajax.php',"widgets="+widgets);


    return true;
}

BUT if in place of 'widgets' I try to post

var random = 'sumo'
makePOSTRequest('/ajax.php',"widgets="+random);

it works.

Not only that, if I开发者_开发问答 place an echo command in the above before 'makepostrequest', 'widgets' get printed out on the clinetside as c[1]c[1]blahblah.

So why does var random = 'sumo' get sent but the 'widgets' variable does not?

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It's because 'widgets' starts with an &, which will mark the beginning of another variable definition in that request. So 'widgets' goes empty.

Try to remove that '&', and parse it accordingly in server-side to correctly read each widget.

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May be it is cached? Clear browser cache and then if it works, add cache expiry in the ajax.php.

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widgets+='&c[1]['+i+']='+col_1.childNodes[i].id;
makePOSTRequest('/ajax.php',"widgets="+widgets);

So you're going to end up with the form-encoded string:

widgets=&c[1][0]=foo&c[1][1]=bar

That is, a widgets parameter with an empty string value, then a c[1][0] parameter with foo value, and so on. Is that what you wanted?

If you actually wanted to pack your whole &c[1][0]=foo&c[1][1]=bar string into the widgets parameter, the string you'd need would be:

widgets=%26c[1][0]=foo%26c[1][1]=bar

turning those ampersand separators into URL-encoded versions so they don't split the form data. To do that, you'd say:

makePOSTRequest('/ajax.php',"widgets="+encodeURIComponent(widgets));