document.getElementById加onClick,onChange,style属性的方法

<a href="javascript:void(0)" id="c1">12322222222222222</a><br>
<select id="s1"><option value="1">111111111111</option><option value="2">222222222222</option></select>
<script>
document.getElementById ("c1").onclick=function()
{
?alert('c');
}
document.getElementById ("s1").onchange=function()
{
?s();
}
function s(){alert('s');}
</script>

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style设置：

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document.getElementById(src).style.display="none";???????