<script type="text/javascript">
function dianji(){
setTimeout("alert('执行成功');",7000);
}
</script>
<button onclick="dianji()">点击</button>
<script type="text/javascript">
var scr=0;
var time=setInterval("times()",1000);
function times(){
document.getElementById("wang").innerHTML=scr++;
}
function tingzhi(){
clearInterval(time);
}
</script>
<p id="wang">0</p>
<button onclick="tingzhi()">停止</button>
<script type="text/javascript">
function shiqu(objec){
if(objec.value.length<4){
alert("长度不够");
objec.focus();
objec.select();
}
}
</script>
<input type="password" onblur="shiqu(this)" />