JavaScript数组

var sum=0
var attr=[70,89,78,90,96,79,88,100,56,95]
for(var i=0;i<attr.length;i++)
{
     if(attr[i]>sum)
     {
         sum=attr[i]
     }
}
 
alert(sum)

var sum=0
var attr=[70,89,78,90,96,79,88,100,56,95]
for(var i=0;i<attr.length;i++)
{       
 
         sum=attr[i]+sum
}
 
alert(sum)

var sum=0
var attr=[70,89,78,90,96,79,88,100,56,95]
for(var i=0;i<attr.length;i++)
{       
 
         sum=attr[i]+sum/attr.length
}
 
alert(sum)

var sum=56
var attr=[70,89,78,90,96,79,88,100,56,95]
for(var i=0;i<attr.length;i++)
{
     if(attr[i]<sum)
     {
         sum=attr[i]
     }
}
 
alert(sum)

<script type="text/javascript">
    var attr = [7,12,16,20,25];
    var reng=prompt("输入")
    for(var i=0;i<attr.length;i++)
    {
        if(attr[i]==reng)
        {
        break ;
        }
        if(i==attr.length-1)
        {
        attr[i+1]   =reng;
        }  
    }
    alert(attr)
</script>

var attr = [9,8,7,6,5,4,3,2,1];
var zj = 0;
for(var i=0;i<attr.length-1;i++)
{
    for(var j=0;j<attr.length-1;j++)
    {
        if(attr[j]>attr[j+1])
        {
            zj = attr[j];
            attr[j] = attr[j+1]
            attr[j+1] = zj;
        }  
    }  
}
alert(attr);

var attr = [1,4,5,3,2,7,3,9];
var a =3;
var sy = -1;
for(var i=0;i<attr.length;i++)
{
    if(a==attr[i])
    {
        sy = i;
        alert("索引号"+i);
        //alert(i);
    }
}
if(sy==-1)
{
    alert("没有找到！");
}