html='<table>';
        var i,size,result;
        url='stock.php';
        $.post(url,
            function(data){
            result  = eval('(' + data + ')');    
            size = result.length;
            for (i = 1; i < size; i++) {
                html += "<tr><td>" + result[i][1] + "</td><td>" + result[i][2]+ "</td><td>" + result[i][3] + "</td></tr>";
            }
        });
        html+='</table>';
        alert(html);

<?php

$url = 'http://data.stock.hexun.com/quotes/stock_4.htm';
$content = @file_get_contents($url);
preg_match('/<table width=\"100%\"[^>]*>(.*)<\/table>/isU', $content,$str);
preg_match_all('/<tr>(.*)<\/tr>/isU', $str[0],$strs);
foreach ($strs[0] as $value){
    //$pingyings = str_replace('__', '', $pingying);
    preg_match_all('/(<td[^>]*>|<th[^>]*>)(.*)(<\/td>|<\/th>|<\/div>)/isU', $value,$strs);
    $zhishu[] = $strs[2];
}

for($i=1,$size=count($zhishu); $i<$size; $i++){
    $zhishu[$i][0] = str_replace('<div>', '', $zhishu[$i][0]);
    //$zhishu[$i][0] = iconv('gbk', 'utf-8', $zhishu[$i][0]);
}
die(JSON($zhishu));


function arrayRecursive(&$array, $function, $apply_to_keys_also = false)
{
    foreach ($array as $key => $value) {
        if (is_array($value)) {
            arrayRecursive($array[$key], $function, $apply_to_keys_also);
        } else {
            $array[$key] = $function($value);
        }

        if ($apply_to_keys_also && is_string($key)) {
            $new_key = $function($key);
            if ($new_key != $key) {
                $array[$new_key] = $array[$key];
                unset($array[$key]);
            }
        }
    }
}

function JSON($array) {
 arrayRecursive($array, 'urlencode', true);
 $json = json_encode($array);
 return urldecode($json);
}

<?php
header("Content-type:text/html;charset=gbk");
$url = 'http://data.stock.hexun.com/quotes/stock_4.htm';
...
...
...
?>

------解决方案--------------------
按你的数据，只能是一维数组
你的循环错误在于
1、起点错了，数组下标从 0 开始，你却从 1
2、明明是一维数组，你却当做二维来处理，自然就文不对题了

数据是三个一组的
for (i = 0; i < size; i+=3) {
 html += "<tr><td>" + result[i] + "</td><td>" + result[i+1]+ "</td><td>" + result[i+2] + "</td></tr>";
}


------解决方案--------------------
用php组成2维的不就行了