input值

<form name="searchForm" method="get" action="search.php" onSubmit="return checkSearchForm()" class="search-form">
<input type="text" name="keywords" id="keyword" class="search-txt"

value="请输入您要搜索的内容" onfocus="if (this.value=='请输入您要搜索的内容') this.value='';"

onblur="if(this.value==''){this.value='请输入您要搜索的内容'}""

<input type="submit" value="搜索" class="search-btn" id="search-btn">
</form>