ASP.NET内容页面中的javascript错误
[英]javascript error in ASP.NET content page
问题描述
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<script type="text/javascript">
function Test1(w) {
document.getElementById('<%=TextBox1.ClientID%>').style.width = w;
return false;
}
Test1(10); // This line arises an error. Why ?
</script>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<input id="Button1" type="button" value="button" onclick="Test1(10)" />
</asp:Content>
I get error when the function Test1(10) is called from the script. 
从脚本调用函数Test1（10）时出现错误。 But when it called on the click of button, it works fine. 但是当它单击按钮时，它可以正常工作。 How can I call the function from the script(OR how I can access the onload() function in an ASP.NET Content Page )? 如何从脚本中调用函数（或如何在ASP.NET Content Page访问onload()函数）？
4 个解决方案
解决方案1
1 2012-01-10 14:04:24
When your call to "Test1()" inside the <script> block happens, that input field is not yet part of the DOM. 当您在<script>块内调用“ Test1（）”时，该输入字段尚未成为DOM的一部分。 Thus the call to getElementById() will return null and the first line of the function will fail. 因此，对getElementById()的调用将返回null并且该函数的第一行将失败。
If you move the <script> block to after the text box, it should work. 如果移动<script>块到文本框后 ，它应该工作。
edit — also you may want to explicitly append "px" to your width. 编辑 -您也可能想在宽度上显式附加“ px”。
解决方案2
0 2012-01-10 14:04:46
try this 尝试这个
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<script type="text/javascript">
function Test1(w) {
document.getElementById('<%=TextBox1.ClientID%>').style.width = w;
return false;
}
window.onload = function() {
Test1(10); // This line arises an error. Why ?
}
</script>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<input id="Button1" type="button" value="button" onclick="Test1(10)" />
</asp:Content>
解决方案3
0 2012-01-10 14:05:05
It's because the textbox doesn't exist when you execute Test1 in the script. 这是因为在脚本中执行Test1时，文本框不存在。 You either have to place the call in a document.ready function or move it further down the page, after the textbox. 您要么必须将调用放置在document.ready函数中，要么将其移至文本框之后的页面下方。
解决方案4
0 2012-01-10 14:22:07
First of all you every time you want to execute javascript code, even directly from the tag ether from events you have to wait to load the dom level. 首先，每次您要执行JavaScript代码时，甚至直接从标记ether中执行事件，都必须等待加载dom级别。 So can do something like : 因此可以做类似的事情：
<script type="text/javascript">
window.onload =function()
{ /* code */ }
</script>
Or execute your code in the "onload" event of the body tag: like 或在body标签的“ onload”事件中执行代码：
<body onload="Test1(10);">
</body>
Or if you use JQuery you can use the above : 或者，如果您使用JQuery，则可以使用上面的代码：
<script type="text/javascript">
$(document).ready(function(){
/* Code to execute */
});
</script>
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