- 创建新的 XMLHttpRequest 对象(Ajax 应用程序的核心):
<script language="javascript" type="text/javascript">
var xmlHttp = new XMLHttpRequest();
</script> - 用 JavaScript 代码捕获和设置字段值
//获取 id 值为 first_name 的表单域
var name = document.getElementById('first_name').value; //修改 id 值为 test 的表单域的值
document.getElementById('test').value = response[0]; - 在 Microsoft 浏览器上创建 XMLHttpRequest 对象
var xmlHttp = false;
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e2) {
xmlHttp = false;
}
} - 以支持多种浏览器的方式创建 XMLHttpRequest 对象
/* Create a new XMLHttpRequest object to talk to the Web server */
var xmlHttp = false;
/*@cc_on @*/
/*@if (@_jscript_version >= 5)
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e2) {
xmlHttp = false;
}
}
@end @*/ if (!xmlHttp && typeof XMLHttpRequest != 'undefined') {
xmlHttp = new XMLHttpRequest();
} - 开始工作:发送Ajax请求
function callServer() {
// Get the city and state from the web form
var city = document.getElementById("city").value;
var state = document.getElementById("state").value; // Build the URL to connect to
var url = "/scripts/getZipCode.php?city=" + escape(city) + "&state=" + escape(state); // Open a connection to the server
xmlHttp.open("GET", url, true); // Setup a function for the server to run when it's done
xmlHttp.onreadystatechange = updatePage; // Send the request
xmlHttp.send(null);
}