html:text disabled和readonly怎么不能改啊

Question

<td>
  <html:text styleId="ypmc" name="appdoc" property="value(ypmc)" styleClass="inputBox" onfocus="this.className='inputBoxMutlineF'" onblur="this.className='inputBox'"/>                         
</td>想要在JAVASCRIPT中把readonly或disabled设置为true document.getElmentById("ypmc").readOnly = true;
 document.getElmentById("ypmc").disabled = true;
 document.getElmentById("ypmc").disabled = disabled;都是报错，“对象不支持此属性或方法”
谁帮忙看下啊

Answer 1

document.getElmentById("ypmc").style.disable=true;

Answer 2

getElmentById
->
getElementById
document.getElementById("ypmc").disabled = true;  or
document.getElementById("ypmc").disabled = false;