效果图
要做出上面的效果图,我们需要对隐藏表单的元素有个简单的了解
隐藏表单的元素的语法格式为:,其功能是在浏览网页时使浏览器不显示这个表单字段元素，但在提交表单时将这个隐藏表单元素的name属性
和value属性值发送给服务器
<?<span style="color: #000000;">php
</span><span style="color: #800080;">$CFQ</span> = <span style="color: #800080;">$_POST</span>["tag"];<span style="color: #008000;">//</span><span style="color: #008000;">判断用户是否单击了计算按钮</span>
<span style="color: #0000ff;">if</span>(<span style="color: #800080;">$CFQ</span> == 1<span style="color: #000000;">)
{
</span><span style="color: #800080;">$addnum1</span> = <span style="color: #800080;">$_POST</span>["addnum1"];<span style="color: #008000;">//</span><span style="color: #008000;">通过$_POST内置数组获取加数</span>
<span style="color: #800080;">$addnum2</span> = <span style="color: #800080;">$_POST</span>["addnum2"<span style="color: #000000;">];
}
</span><span style="color: #0000ff;">else</span><span style="color: #000000;">{
</span><span style="color: #800080;">$addnum1</span> = <span style="color: #800080;">$addnum2</span> = 0<span style="color: #000000;">;
}
</span><span style="color: #800080;">$sum</span> = <span style="color: #800080;">$addnum1</span> + <span style="color: #800080;">$addnum2</span><span style="color: #000000;">;
</span>?><span style="color: #000000;">
在表单中输入两个整数
</span><form name = "form1" method = "post" action = "#">
<input type = "hidden" name = "tag" size = "4" value="1"> <!--值用于做相等判断-->
<input type="text" name="addnum1" size="4" value="<?php echo <span style="color: #800080;">$addnum1</span>;?>">
+
<input type="text" name="addnum2" size="4" value="<?php echo <span style="color: #800080;">$addnum2</span>;?>">
=
<?php <span style="color: #0000ff;">echo</span> <span style="color: #800080;">$sum</span>;?><br> <!--输出计算结果-->
<br><input type="submit" name="Submit" value="计算">
<input type="reset" name="Submit" value="重置">
</form>
