简单的复选框javascript does not work

Question

复选框应该被选中，但它不起作用。我很困惑。

<script type="text/javascript"> 

function check() { 
document.getElementById("1").checked = true; 
} 
</script> 

<form> 
<input id="1" type="checkbox" name="please check" value="1">please check<br> 
</form> 

Answer 1

我把它称为对窗口的Onload凡调用只是传递函数名

<script type="text/javascript"> 
    window.onload=check; 

    function check() { 
    document.getElementById("1").checked = true; 
    } 
    </script> 

    <form> 
    <input id="1" type="checkbox" name="please check" value="1">please check<br> 
    </form> 

Answer 2

以其他方式排序并摆脱该函数，这将确保在脚本运行时复选框存在。

jsFiddle

<form> 
    <input id="1" type="checkbox" name="please check" value="1">please check<br> 
</form> 
<script type="text/javascript"> 
    document.getElementById("1").checked = true; 
</script> 

可选择地把它放在文件就绪（jQuery的）或窗口负载。

jsFiddle

window.addEventListener('load', check); 
function check() { 
    document.getElementById("1").checked = true; 
} 

Answer 3

试试这个：

<script type="text/javascript"> 

function check() { 
document.getElementById("check1").checked = true; 
} 

window.onload = check; 
</script> 

<form> 
<input id="check1" type="checkbox" name="please check" value="1">please check<br> 
</form> 

refer this link also。