如何在jquery/PHP中通过post传递选项字段和输入框的值

我有一个类似

<div id="searchbar">
<form>
<select name="Cars">
<option value="big">Big Cars</option>
<option value="small">Small Cars</option>
</select>
<input type ='text' name="searchkey" id ="search" onblur ='setTimeout('removeSearchSuggestions()', 20);' onkeyup ='getSearchSuggestions(this.value);'/>
&nbsp;
<br/>
<div id = 'searchsuggest'></div>
<input type ='submit' value = 'Search' />
</form>
</div>

function getSearchSuggestions(value){
   if (value !=""){
   $.post("searchSuggest.php", {searchPart:value}, function(data) {
     $("#searchsuggest").html(data);
     doSearchCSS();
   });
   } else {
    removeSearchSuggestions();
    }
  }

所以searchSuggest可以访问"searchPart"，即输入框中的值。我在修改一些东西，为了一个没有选择的案子。如何修改jquery函数以访问searchSuggest.php中的选定选项?

谢谢!