input 显示很隐藏

function selectStr()

{

if(document.getElementById('Industry').value== '')

{

document.getElementById("gs").style.display="none";

}

else{

       document.getElementById("gs").style.display="block";

}

}

/**

案例

**/

<li><span class="f-l"><em class="g-c-c0"> * </em>想代理产品</span>

<select name="category" id="Industry" onchange="selectStr()">

<option value="">请选择行业类目</option>

<foreach name="Industry" item="menu">

<option value="{$menu.id}">{$menu.cn}</option>

</foreach>

</select>

<span id="gs" class="buchong m_ds_n"><input type="text" id="qita" name="gs" class="input_text g-ml-10" placeholder="可在这里补充想要经营的产品，最多20字"></span>

<span id="category-notice" class="m_it_ts">请选择行业类目</span>

</li>