按钮值显示未定义

Question

[pure javascript code without the html body] 
<script language="Javascript"> 
    [ creating buttons with the alphabets on it and its values the same] 

    for(var a=1;a<=26;a++) 
    { 
    document.write("<input type='button' size='1' value="+String.fromCharCode(a +64)+" id='btn"+a+"' onclick='see()' >"); 
    } 


document.write("<input type='text' size='10' id='box1' style='background-color:red'>")    

[normal textbox which should contain the data] 
    function see() 
     { 
     [trying to put the value of button on textbox on buttonclick but gives me undefined] 


     var text; 
     text=*document.getElementsByTagName*("button").value; 
     document.getElementById("box1").value=text; 
     } 

</script> 

我甚至凭身份证试图document.getElementsByTagName或给出不确定的地方，因为我想要的按钮的值对文本框.. 我用for循环，因为我必须创造约26按钮

Answer 1

"...value='" + String.fromCharCode(a +64) + "'..." 

您错过了单引号。