js 觸發select onchange事件代碼

2019-11-20 20:55:37

字體：大中小

來源：轉載

供稿：網友

select 或text的onchange事件需要手動（通過鍵盤輸入）改變select或text的值才能觸發，如果在js中給select或text賦值，則無法觸發onchang事件，
例如，在頁面加載完成以后，需要觸發一個onChange事件，在js中用document.getElementById("province").value="湖北";直接給select或text賦值是不行的，要想實現手動觸發onchange事件，需要在js給select賦值后，加入下面的語句

document.getElementById("province").fireEvent('onchange') 來實現,

復制代碼代碼如下:

 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> 
<title>無標題文檔</title> 
<script type="text/javascript"> 
var provinces = new Array(); 
provinces["湖北"] = ["武漢","襄陽","隨州","宜昌","十堰"]; 
provinces["四川"] = ["成都","內江","達州"]; 
provinces["河南"] =["鄭州","南陽","信陽","漯河"]; 
function changeProvince() 
{ 
var prov = document.getElementById("province").value; 
var city =document.getElementById("city"); 
city.options.length =0; 
for(var i in provinces[prov]) 
{ 
city.options.add(new Option(provinces[prov][i],provinces[prov][i])); 
} 
} 
window.onload = function(){ 
var province = document.getElementById("province"); 

for(var index in provinces) 
{ 
//alert(index); 
province.options.add(new Option(index,index)); 
} 
province.fireEvent("onchange"); 
}; 
</script> 
</head> 
<body> 
省份:<select id="province" onchange= "changeProvince()"></select> 
城市:<select id="city"></select> 
</body> 
</html> 