移动端版本兼容js

<script type="text/javascript">
        var phoneWidth = parseInt(window.screen.width);
        var phoneScale = phoneWidth/640;

        var ua = navigator.userAgent;
        if (/Android (\d+\.\d+)/.test(ua)){
            var version = parseFloat(RegExp.$1);
            // andriod 2.3
            if(version>2.3){
                document.write(‘<meta name="viewport" content="width=640, minimum-scale = ‘+phoneScale+‘, maximum-scale = ‘+phoneScale+‘, target-densitydpi=device-dpi">‘);
            // andriod 2.3以上
            }else{
                document.write(‘<meta name="viewport" content="width=640, target-densitydpi=device-dpi">‘);
            }
            // 其他系统
        } else {
            document.write(‘<meta name="viewport" content="width=640, user-scalable=no, target-densitydpi=device-dpi">‘);
        }
        
        if(IsPC()){
            document.write(‘<meta name="viewport" content="width=640, user-scalable=no, target-densitydpi=device-dpi">‘);
        }

        function IsPC() {  
           var userAgentInfo = navigator.userAgent;  
           var Agents = new Array("Android", "iPhone", "SymbianOS", "Windows Phone", "iPad", "iPod");  
           var flag = true;  
           for (var v = 0; v < Agents.length; v++) {  
               if (userAgentInfo.indexOf(Agents[v]) > 0) { flag = false; break; }  
           }  
           return flag;  
        }              
</script>