Specified content cannot be selected through script control_Typical special effects

<script type="text/javascript">  
disableSelection(document.body) //disable text selection on entire body of page  
</script>  

<script type="text/javascript">  
var somediv=document.getElementById("mydiv")  
disableSelection(somediv) //disable text selection within DIV with id="mydiv"  
</script>  

<script type="text/javascript">  
var alltables=document.getElementsByTagName("table")  
for (var i=0; i<alltables.length; i++)  
disableSelection(alltables[i]) //disable text selection within all tables on the page  
</script>

<script type="text/javascript"> 
//more javascript from http://www.smallrain.net 
function disableSelection(target){ 
if (typeof target.onselectstart!="undefined") //IE route 
    target.onselectstart=function(){return false} 
else if (typeof target.style.MozUserSelect!="undefined") //Firefox route 
    target.style.MozUserSelect="none" 
else //All other route (ie: Opera) 
    target.onmousedown=function(){return false} 
target.style.cursor = "default" 
} 

//Sample usages 
//disableSelection(document.body) //Disable text selection on entire body 
//disableSelection(document.getElementById("mydiv")) //Disable text selection on element with id="mydiv" 

</script>
<div id="test" style="background:#f1f1f1;border:1px #000  dotted">这里不能选择</div> 
<script type="text/javascript"> 
var somediv=document.getElementById("test") 
disableSelection(somediv) //disable text selection within DIV with id="mydiv" 
</script>