将html值传递到javascript函数中 [英] Passing html values into javascript functions
问题描述
我正在做一个javascript函数，需要在其中确认输入.我编写了以下代码，但即使输入了有效值，它也会给出负值，即"else"部分.有人可以提出解决方案吗?
I was making a javascript function in which I need to confirm the input. I wrote the following code but its giving negative value i.e. "else" part even if i enter a valid value. Can some one please suggest a solution?
HTML文件:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Javascript App</title>
<script type="text/javascript" src="app1.js">
</script>
</head>
<body><h1 id="heading1" style="text-align:center; height:auto; width:auto; font-family:'Arial Black', Gadget, sans-serif">Determinant of a nxn matrix</h1>
<p id="paragraph1" style="font-family:'Arial Black', Gadget, sans-serif"> This program allows you to compute the determinant of a nxn matrix</p>
<p>
Input the order of the matrix
<br />
<input type="text" maxlength="3" name="value" />
<input type="button" value="submit" onclick="verifyorder(value)" />
</p>
<p id="error"></p>
<p id="detspace"></p>
</body>
</html>
JavaScript文件:
Javascript File:
function verifyorder(order){
;
if(order>0){
return true;
}
else{
alert("Sorry, you need to enter a positive integer value, try again");
document.getElementById('error').innerHTML="Sorry, you need to enter a positive integer value, try again";
}
}
推荐答案
这是 JSfiddle演示
我更改了您的HTML，并为您输入的文本字段提供了一个值ID.我为您的verifyorder函数删除了传递的参数，而是使用document.getElementById();来获取文本字段的内容；然后我用+order将str转换为值，以便您可以检查它是否大于零:
I changed your HTML and give your input textfield an id of value. I removed the passed param for your verifyorder function, and instead grab the content of your textfield by using document.getElementById(); then i convert the str into value with +order so you can check if it's greater than zero:
<input type="text" maxlength="3" name="value" id='value' />
<input type="button" value="submit" onclick="verifyorder()" />
</p>
<p id="error"></p>
<p id="detspace"></p>
function verifyorder() {
var order = document.getElementById('value').value;
if (+order > 0) {
alert(+order);
return true;
}
else {
alert("Sorry, you need to enter a positive integer value, try again");
document.getElementById('error').innerHTML = "Sorry, you need to enter a positive integer value, try again";
}
}
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