js实现放大缩小页面

<script type="text/JavaScript">

var size = 1.0;  
function zoomout() {  
 size = size + 0.1;  
 set(); 
}  


function zoomin() {  
 size = size - 0.1;  
 set();  
}  


function set() {  
 //document.body.style.cssText = document.body.style.cssText + \'; -webkit-transform: scale(\' + size + \');-webkit-transform-origin: 0 0;\';   
 //document.body.style.cssText = document.body.style.cssText + \'; -webkit-transform: scale(\' + size + \'); \'; 
 //$(body).css("width","120%);
document.body.style.zoom = size;
document.body.style.cssText += \'; -moz-transform: scale(\' + size + \');-moz-transform-origin: 0 0; \';     //
} 
    </script>