<html> <head> <script type="text/javascript"> function moveNext(object,index){ if(object.value.length==4){ document.forms[0].elements[index+1].focus(); } } function showResult(){ var f=document.forms[0]; var result=""; for(var i=0;i<4;i++){ result+=f.elements[i].value; } alert(result); } </script> </head> <body onload="document.forms[0].elements[0].focus();"> <form> <input type="text" size="3" maxlength="4" onkeyup="moveNext(this,0);"> <input type="text" size="3" maxlength="4" onkeyup="moveNext(this,1);"> <input type="text" size="3" maxlength="4" onkeyup="moveNext(this,2);"> <input type="text" size="3" maxlength="4" onkeyup="moveNext(this,3);"> <input type="button" value="显示" onclick="showResult();"> </form> </body> </html>
原文：http://www.cnblogs.com/qq-757617012/p/4179191.html