<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.hide_text {
display: none;
}
</style>
</head>
<body>
<select name="TOURINC" class="TOURINC" autocomplete="off">
<option value="0">----</option>
<option value="58">ISTANBUL</option>
<option value="70">BEIJING</option>
<option value="69">KHARKIV</option>
<option value="68">LONDON</option>
<option value="67">ANTALIA</option>
</select>
<br>
<br>
/*в css class="hide_text" по умолчанию скрывает данный DIV*/
<div id="info_tours">
<div id="58" class="hide_text">ISTANBUL - описание бла, бла, бла...</div>
<div id="70" class="hide_text">BEIJING- описание бла, бла, бла...</div>
<div id="69" class="hide_text">KHARKIV- описание бла, бла, бла...</div>
<div id="68" class="hide_text">LONDON- описание бла, бла, бла...</div>
<div id="67" class="hide_text">ANTALIA- описание бла, бла, бла...</div>
</div>
</body>
<script>
var sel = document.querySelector('.TOURINC');
var tours = document.querySelectorAll('#info_tours div');
sel.addEventListener('change', function(e) {
for (t in [].slice.call(tours)) {
if (tours[t].id == e.target.value) {
tours[t].classList.remove('hide_text');
} else {
tours[t].classList.add('hide_text');
}
}
}, false);
</script>
</html>