<script language="javascript"> 
var o = document.body; 
//创建链接 
function createA(url,text) 
{ 
var a = document.createElement("a"); 
a.href = http://www.mamicode.com/url;
a.innerHTML = text; 
a.style.color = "red"; 
o.appendChild(a); 
} 
createA("http://www.ffasp.com/","网页教学网"); 
</script> 

<script language="javascript"> 
var o = document.body; 
//创建DIV 
function createDIV(text) 
{ 
var div = document.createElement("div"); 
div.innerHTML = text; 
o.appendChild(div); 
} 
createDIV("网页教学网：http://www.ffasp.com/");    
</script> 

<script language="javascript"> 
var o = document.body; 
//创建表单项 
function createInput(sType,sValue) 
{ 
var input = document.createElement("input"); 
input.type = sType; 
input.value = http://www.mamicode.com/sValue;
o.appendChild(input); 
} 
createInput("button","ooo"); 
</script> 

<script language="javascript"> 
var o = document.body; 
//创建表格 
function createTable(w,h,r,c) 
{ 
var table = document.createElement("table"); 
var tbody = document.createElement("tbody"); 
table.width = w; 
table.height = h; 
table.border = 1;    
for(var i=1;i<=r;i++) 
{ 
var tr = document.createElement("tr"); 
for(var j=1;j<=c;j++) 
{ 
var td = document.createElement("td"); 
td.innerHTML = i + "" + j; 
//td.appendChild(document.createTextNode(i + "" + j)); 
td.style.color = "#FF0000"; 
tr.appendChild(td); 
} 
tbody.appendChild(tr);    
} 
table.appendChild(tbody); 
o.appendChild(table); 
} 
createTable(270,270,9,9); 

5.创建select

jquery 的话这样
<select id="selectid">
</select>
 
$(function(){
   $("#selectid").click(function(){
        $("#selectid").append("<option value=http://www.mamicode.com/‘"+entity+"‘>"+entity+"</option>");//entity 变量
}); 
  
});

js的话
function padd(){
 var objOption = document.createElement("OPTION");
 objOption.text= 2; 
 objOption.value=http://www.mamicode.com/2; 
 document.getElementById("padd").options.add(objOption);
}

</script>