content"width=640,user-scalable=no" 然后再进行固定尺寸的px设计？

content"width=640,user-scalable=no" 然后再进行固定尺寸的px设计？ 竟然也可以达到自适应的布局在手机上面
咱们不都是通常viewport content="width=device-width么 那么上面这种有没有什么坑呢 ，那么以后我是t content="width=device-width css3媒体查询 还是用content"width=640,user-scalable=no"这样的方法呢 我需要兼容手机浏览器和apk的webview

回复内容：

結論：content"width=640,user-scalable=no" 是一個很好的解決方案，荔枝FM,人人都是播客的移動站使用的就是此方案

固定宽度，viewport 缩放

视觉稿、页面宽度、viewport width 使用统一宽度，利用浏览器自身缩放完成适配。页面样式（包括图像元素）完全按照视觉稿的尺寸，使用定值单位 （px、em）即可完成。

优点：

• 开发简单 缩放交给浏览器，完全按视觉稿切图。
• 还原精准 绝对等比例缩放，可以精准还原视觉稿（不考虑清晰度的情况下）。
• 测试方便 在PC端即可完成大部分测试，手机端只需酌情调整一些细节（比如图标、字体混合排列时，因为字体不同造成的对齐问题）。

存在的问题：

• 像素丢失 对于一些分辨率较低的手机，可能设备像素还未达到指定的 viewport 宽度，此时屏幕的渲染可能就不准确了。比较常见的是边框“消失”了，不过随着手机硬件的更新，这个问题会越来越少的。
• 缩放失效 某些安卓机不能正常的根据 meta 标签中 width 的值来缩放 viewport，需要配合initial-scale 。
• 文本折行 存在于缩放失效的机型中，某些手机为了便于文本的阅读，在文本到达 viewport 边缘（非元素容器的边缘）时即进行折行，而当 viewport 宽度被修正后，浏览器并没有正确的重绘，所以就发现文本没有占满整行。一些常用的段落性文本标签会存在该问题。

缩放失效问题需通过 js 动态设定 initial-scale。

利用 rem 布局

依照某特定宽度设定 rem 值（即 html 的 font-size），页面任何需要弹性适配的元素，尺寸均换算为 rem 进行布局；当页面渲染时，根据页面有效宽度进行计算，调整 rem 的大小，动态缩放以达到适配的效果。利用该方案，还可以根据 devicePixelRatio 设定 initial-scale 来放大 viewport，使页面按照物理像素渲染，提升清晰度。

优点：

• 清晰度高，能达到物理像素的清晰度。
• 能解决 DPR 引起的“1像素”问题。
• 向后兼容较好，即便屏幕宽度增加、PPI 增加该方案依旧适用。

缺点：

• 适配 js 需尽可能早进入，减少（避免）viewport 变化引起的重绘。
• 某些Android机会丢掉 rem 小数部分。
• 需要预编译库进行单位转换。

（轉自MobileWeb 适配总结） 别的不多说了，强烈建议看看前几天刚写的一篇文章：使用Flexible实现手淘H5页面的终端适配 应该能让你找到需要的答案 你在用的可能是:

 <span class="nt"><meta</span> <span class="na">name=</span><span class="s">"viewport"</span> <span class="na">content=</span><span class="s">"target-densitydpi=device-dpi,width=640,user-scalable=no"</span> <span class="nt">/></span>

这种做法就本质上是对界面进行线性缩放来适应不同大小的屏幕。对于一定尺寸范围内的设备是可以的。但如果想开发出跨越平板和手机的界面则不太合适。因为手机和平板屏幕尺寸差异太大，会导致缩放太大而是界面元素显得不太和谐。所以最好采用非线性缩放的办法。

<span class="c1">//首先检查浏览器类型</span>
<span class="kd">var</span> <span class="nx">browser</span> <span class="o">=</span> <span class="nx">getBrowser</span><span class="p">();</span>

<span class="k">if</span> <span class="p">(</span><span class="nb">window</span><span class="p">.</span><span class="nx">top</span> <span class="o">===</span> <span class="nb">window</span><span class="p">)</span> <span class="p">{</span>
	<span class="kd">var</span> <span class="nx">s</span><span class="p">,</span> <span class="nx">t</span><span class="p">,</span> <span class="nx">sw</span><span class="p">;</span>
	<span class="k">if</span> <span class="p">(</span><span class="nx">browser</span> <span class="o">===</span> <span class="s1">'Gecko'</span><span class="p">)</span> <span class="p">{</span>
		<span class="nx">s</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span><span class="p">));</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">write</span><span class="p">(</span><span class="s1">'<meta name="viewport" content="width='</span> <span class="o">+</span> <span class="mi">100</span> <span class="o">/</span> <span class="nx">s</span> <span class="o">+</span> <span class="s1">'%, user-scalable=no, initial-scale='</span> <span class="o">+</span> <span class="nx">s</span> <span class="o">+</span> <span class="s1">'"/>'</span><span class="p">);</span>
	<span class="p">}</span> <span class="k">else</span> <span class="k">if</span> <span class="p">(</span><span class="nx">browser</span> <span class="o">===</span> <span class="s1">'Trident'</span><span class="p">)</span> <span class="p">{</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">write</span><span class="p">(</span><span class="s1">'<meta name="viewport" content="width=device-width, user-scalable=no"/>'</span><span class="p">);</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">documentElement</span><span class="p">.</span><span class="nx">style</span><span class="p">.</span><span class="nx">zoom</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span><span class="p">));</span>
	<span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
		<span class="nx">t</span> <span class="o">=</span> <span class="nb">document</span><span class="p">.</span><span class="nx">createElement</span><span class="p">(</span><span class="s1">'meta'</span><span class="p">);</span>
		<span class="nx">t</span><span class="p">.</span><span class="nx">name</span> <span class="o">=</span> <span class="s1">'viewport'</span><span class="p">;</span>
		<span class="nx">t</span><span class="p">.</span><span class="nx">content</span> <span class="o">=</span> <span class="s1">'width=device-width, user-scalable=no, initial-scale=1'</span><span class="p">;</span>
		<span class="nb">document</span><span class="p">.</span><span class="nx">head</span><span class="p">.</span><span class="nx">appendChild</span><span class="p">(</span><span class="nx">t</span><span class="p">);</span>
		<span class="nx">sw</span> <span class="o">=</span> <span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span><span class="p">);</span>
		<span class="k">if</span> <span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">min</span><span class="p">(</span><span class="nx">screen</span><span class="p">.</span><span class="nx">width</span> <span class="o">/</span> <span class="nb">window</span><span class="p">.</span><span class="nx">innerWidth</span><span class="p">,</span> <span class="nx">screen</span><span class="p">.</span><span class="nx">height</span> <span class="o">/</span> <span class="nb">window</span><span class="p">.</span><span class="nx">innerHeight</span><span class="p">)</span> <span class="o">></span> <span class="mi">1</span><span class="p">)</span> <span class="p">{</span>
			<span class="nb">document</span><span class="p">.</span><span class="nx">documentElement</span><span class="p">.</span><span class="nx">style</span><span class="p">.</span><span class="nx">zoom</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nx">sw</span> <span class="o">/</span> <span class="nx">devicePixelRatio</span><span class="p">);</span>
		<span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
			<span class="nx">s</span> <span class="o">=</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nx">sw</span><span class="p">);</span>
			<span class="nx">t</span><span class="p">.</span><span class="nx">content</span> <span class="o">=</span> <span class="s1">'width='</span> <span class="o">+</span> <span class="mi">100</span> <span class="o">/</span> <span class="nx">s</span> <span class="o">+</span> <span class="s1">'%, user-scalable=no, initial-scale='</span> <span class="o">+</span> <span class="nx">s</span><span class="p">;</span>
		<span class="p">}</span>
	<span class="p">}</span>
<span class="p">}</span>

<span class="kd">function</span> <span class="nx">calcRato</span><span class="p">(</span><span class="nx">sw</span><span class="p">)</span> <span class="p">{</span>
	<span class="c1">//离散放大级别</span>
	<span class="kd">var</span> <span class="nx">step</span> <span class="o">=</span> <span class="mf">0.125</span><span class="p">;</span>
	<span class="c1">//基准宽度为320px</span>
	<span class="kd">var</span> <span class="nx">zoom</span> <span class="o">=</span> <span class="nx">sw</span> <span class="o">/</span> <span class="mi">320</span><span class="p">;</span>
	<span class="c1">//放大时不使用线性算法</span>
	<span class="k">if</span> <span class="p">(</span><span class="nx">zoom</span> <span class="o">></span> <span class="mi">1</span><span class="p">)</span> <span class="p">{</span>
		<span class="nx">zoom</span> <span class="o">=</span> <span class="nb">Math</span><span class="p">.</span><span class="nx">floor</span><span class="p">(</span><span class="nb">Math</span><span class="p">.</span><span class="nx">sqrt</span><span class="p">(</span><span class="nx">zoom</span><span class="p">)</span> <span class="o">/</span> <span class="nx">step</span><span class="p">)</span> <span class="o">*</span> <span class="nx">step</span><span class="p">;</span>
	<span class="p">}</span>
	<span class="k">return</span> <span class="nx">zoom</span><span class="p">;</span>
<span class="p">}</span>

对，我也是用这种方法比较方便。不过由于宽高等比缩放后，在元素定位布局时很多手机的屏幕就不够高，因此还是得媒体查询做些细节上的调节 用过这种代码写hybrid app效果还行，核心区别就在于它没有媒体查询，手机，平板都长一个样，等比缩放不仔细看效果也不差（毕竟会变形），如果你只需要开发个大部分机型适配的页面，我觉得这么写挺好

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