javascript 大写字母小写字母之间的转换

toLowerCase() //小写

toUpperCase() //大写

<script type="text/javascript" language="javascript">
　　var str = "acBd";
　　alert(str.toLowerCase()); // = alert("acbd");
　　alert(str.toUpperCase()); // = alert("ABCD");
</script>

 

<input type="text" id="txt_Name" onkeydown="exchange()" onblur="exchange()" onkeyup="exchange()"/>
       
<script type="text/javascript">       
          function exchange(){         
              var txt_Name=document.getElementById("txt_Name");
               txt_Name.value=txt_Name.value.toUpperCase();                 
          }
 </script>