我們先看一下三種算法以及在各種瀏覽器下的表現(xiàn)。
第一種： 直接操作dom。
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>New Web Project</title>
</head>
<body>
<script>
microtime = function(get_as_float) {
var now = new Date().getTime() / 1000;
var s = parseInt(now, 10);
return (get_as_float) ? now : (Math.round((now - s) * 1000) / 1000) + ' ' + s;
}
var m1 = microtime(true);
var table = document.createElement("table");
table.border = 1;
var tbody = document.createElement("tbody");
for(var i = 0; i < 1000; i++ ) {
var tr = document.createElement("tr");
for(var j = 0; j < 5; j++ ) {
var td = document.createElement("td");
td.appendChild(document.createTextNode("cell "+i+","+j));
tr.appendChild(td);
}
tbody.appendChild(tr);
}
table.appendChild(tbody);
//chrome 0.028
//ie6 0.65
//ie7 0.40
//ie8 0.40
//ie9 0.35
//firefox14 0.035
//opera12 0.03
//safari5.17 0.014
document.body.appendChild(table);
var m2 = microtime(true);
alert(m2-m1);
</script>
</body>
</html>
第二種，借助借助createDocumentFragment。
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>New Web Project</title>
</head>
<body>
<script>
microtime = function(get_as_float) {
var now = new Date().getTime() / 1000;
var s = parseInt(now, 10);
return (get_as_float) ? now : (Math.round((now - s) * 1000) / 1000) + ' ' + s;
}
var m1 = microtime(true);
var table = document.createElement("table");
table.border = 1;
var tbody = document.createElement("tbody");
var fragment = document.createDocumentFragment();
for(var i = 0; i < 1000; i++ ) {
var tr = document.createElement("tr");
for(var j = 0; j < 5; j++ ) {
var td = document.createElement("td");
td.appendChild(document.createTextNode("cell "+i+","+j));
tr.appendChild(td);
}
fragment.appendChild(tr);
}
tbody.appendChild(fragment);
table.appendChild(tbody);
//chrome 0.03
//ie6 0.68
//ie7 0.43
//ie8 0.43
//ie9 0.37
//firefox14 0.03
//opera12 0.04
//safari5.17 0.023
document.body.appendChild(table);
var m2 = microtime(true);
alert(m2-m1);
</script>
</body>
</html>
第三種：借助js的原生表格操作方法
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>New Web Project</title>
</head>
<body>
<script>
microtime = function(get_as_float) {
var now = new Date().getTime() / 1000;
var s = parseInt(now, 10);
return (get_as_float) ? now : (Math.round((now - s) * 1000) / 1000) + ' ' + s;
}
var m1 = microtime(true);
var table = document.createElement("table");
table.border = 1;
var tbody = document.createElement("tbody");
table.appendChild(tbody);
for(var i = 0; i < 1000; i++ ) {
tbody.insertRow(i);
for(var j = 0; j < 5; j++ ) {
tbody.rows[i].insertCell(j);
tbody.rows[i].cells[j].appendChild(document.createTextNode("cell "+i+","+j));
}
var tr = document.createElement("tr");
tbody.appendChild(tr);
}
//chrome 0.19
//ie9 0.18
//ie8 0.25
//ie7 8.50
//ie6 20.45
//firefox14 0.065
//opera12 0.25
//safari5.17 0.18
document.body.appendChild(table);
var m2 = microtime(true);
alert(m2-m1);
</script>
</body>
</html>
以上可以看出用原生的js創(chuàng)建表格效率最好，借助createDocumentFragment優(yōu)勢(shì)不是很大（并不像網(wǎng)上說的那么明顯），借助insertRow和insertCell等在ie6、7下效率太低，不建議使用。
對(duì)第一種算法簡單的優(yōu)化了一下：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>New Web Project</title>
</head>
<body>
<script>
microtime = function(get_as_float) {
var now = new Date().getTime() / 1000;
var s = parseInt(now, 10);
return (get_as_float) ? now : (Math.round((now - s) * 1000) / 1000) + ' ' + s;
}
var m1 = microtime(true);
var table = document.createElement("table");
table.border = 1;
var tbody = document.createElement("tbody");
var i = 1000;
while(i--){
var tr = document.createElement("tr"), j = 5;
while(j--){
var td = document.createElement("td");
td.appendChild(document.createTextNode("cell "+i+","+j));
tr.appendChild(td);
}
tbody.appendChild(tr);
}
table.appendChild(tbody);
//chrome 0.03
//ie6 0.66
//ie7 0.41
//ie8 0.41
//ie9 0.35
//firefox14 0.03
//opera12 0.03
//safari5.17 0.013
document.body.appendChild(table);
var m2 = microtime(true);
alert(m2-m1);
</script>
</body>
</html>
總結(jié)：對(duì)dom操作盡量使用createElement和appendChild，對(duì)于js內(nèi)核提供的一些特殊方法慎用。
