java - While using struts html tags, How do I get the value of a textbox using its property attribute? Is there any other way to get the value? -

    function validate(){     var username = document.getelementbyproperty("username").value;     var password = document.getelementbyproperty("password").value;     if((username == null ||username =='') || (password == null||password=='')){      x=document.getelementbyid("error");      x.innerhtml = "username or password cannot blank";     else{        document.getelementbyid("loginform").submit();     }       <form id="loginform" action="login.do" method="post">     username:<html:text property="username"></html:text>     password:<html:password property="password"></html:password>     <html:button onclick="validate()"></html:button>     </form> 

the above code not working , unable values in textbox validation... please me out in issue...

function validate(){     var username = document.getelementbyid("username").value;     var password = document.getelementbyid("password").value; }   <form id="loginform" action="login.do" method="post">     username:<html:text property="username" styleid="username"></html:text>     password:<html:password property="password" styleid="password"></html:password>     <html:button onclick="validate()"></html:button> </form>