blocks|key|505926|text|因为您的lol现在是局部变量，所以使用var关键字声明任何变量是一种好的做法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|505927|这可能对你有用：|505928|function+kk(){
++var+lol+=+document.getElementById('lolz').value;
++alert(lol);
}|code-block|syntax|javascript|505929|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

<p>as your lol is local variable now, its good practice to use var keyword for declaring any variables.</p>

<p>this may work for you :</p>

<pre><code>function kk(){
  var lol = document.getElementById('lolz').value;
  alert(lol);
}
</code></pre>


blocks|key|289228|text|<script+type="text/javascript">
function+kk(){
++++var+lol+=+document.getElementById('lolz').value;
++++alert(lol);
}


</script>

<body+onload="onload();">
++++<input+type="text"+name="enter"+class="enter"+id="lolz"+value=""/>
++++<input+type="button"+value="click"+onclick="kk();"/>
</body>|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|289229|使用这个|unstyled|289230|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>&lt;script type="text/javascript"&gt;
function kk(){
    var lol = document.getElementById('lolz').value;
    alert(lol);
}


&lt;/script&gt;

&lt;body onload="onload();"&gt;
    &lt;input type="text" name="enter" class="enter" id="lolz" value=""/&gt;
    &lt;input type="button" value="click" onclick="kk();"/&gt;
&lt;/body&gt;
</code></pre>

<p>use this</p>


blocks|key|289258|text|以上所有的解决方案都很有用。他们用了这条线|type|unstyled|depth|inlineStyleRanges|entityRanges|data|289259|lol+=+document.getElementById('lolz').value;|code-block|syntax|javascript|289260|在函数function+kk()内部。|offset|length|style|CODE|289261|我的建议是，您可以从另一个函数fun_inside()调用该变量|289262|function+fun_inside()+{++++
++++lol+=+document.getElementById('lolz').value;
}
function+kk()+{
++++fun_inside();
++++alert(lol);
}|289263|当您构建复杂的项目时，它会很有用。|289264|entityMap^0|0|0|3|D|0|F|C|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@$I|10|J|11|K|L]]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|T|$]]

<p>All the above solutions are useful. And they used the line</p>
<pre><code>lol = document.getElementById('lolz').value;
</code></pre>
<p>inside the function <code>function kk()</code>.</p>
<p>What I suggest is, you may call that variable from another function <code>fun_inside()</code></p>
<pre><code>function fun_inside() {    
    lol = document.getElementById('lolz').value;
}
function kk() {
    fun_inside();
    alert(lol);
}
</code></pre>
<p>It can be useful when you built complex projects.</p>


blocks|key|506026|text|<script>
function+subadd(){
subadd=+parseFloat(document.forms[0][0].value)+%2B+parseFloat(document.forms[0][1].value)+
window.alert(subadd)++
}
</script>

<body>
<form>
<input+type="text"+>%2B
<input+type="text"+>
<input+type="button"+value="add"+onclick="subadd()">
</form>
</body>|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|506027|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&lt;script&gt;
function subadd(){
subadd= parseFloat(document.forms[0][0].value) + parseFloat(document.forms[0][1].value) 
window.alert(subadd)  
}
&lt;/script&gt;

&lt;body&gt;
&lt;form&gt;
&lt;input type="text" &gt;+
&lt;input type="text" &gt;
&lt;input type="button" value="add" onclick="subadd()"&gt;
&lt;/form&gt;
&lt;/body&gt;
</code></pre>


blocks|key|506048|text|document.getElementById('id').value|type|unstyled|depth|inlineStyleRanges|entityRanges|data|506049|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

<p>document.getElementById('id').value</p>


blocks|key|289371|text|这不起作用的原因是因为变量不会随着文本框的变化而改变。当它最初运行代码时，它会获得textbox的值，但之后就再也不会调用了。但是，当您在函数中定义变量时，每次调用函数时，变量都会更新。然后向变量发出警报，该变量现在等于文本框的输入。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|289372|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

<p>The reason that this doesn't work is because the variable doesn't change with the textbox. When it initially runs the code it gets the value of the textbox, but afterwards it isn't ever called again. However, when you define the variable in the function, every time that you call the function the variable updates. Then it alerts the variable which is now equal to the textbox's input.</p>


blocks|key|289378|text|<input+type="password"id="har">
<input+type="submit"value="get+password"onclick="har()">
<script>
++++function+har()+{
++++++++var+txt_val;
++++++++txt_val+=+document.getElementById("har").value;
++++++++alert(txt_val);
++++}
</script>|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|289379|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&lt;input type="password"id="har"&gt;
&lt;input type="submit"value="get password"onclick="har()"&gt;
&lt;script&gt;
    function har() {
        var txt_val;
        txt_val = document.getElementById("har").value;
        alert(txt_val);
    }
&lt;/script&gt;
</code></pre>


<p>How go get an input text value in JavaScript?</p>

<pre><code>&lt;script language="javascript" type="text/javascript"&gt;
    lol = document.getElementById('lolz').value;
    function kk(){
    alert(lol);
    }
&lt;/script&gt;

&lt;body&gt;
    &lt;input type="text" name="enter" class="enter" value="" id="lolz"/&gt;
    &lt;input type="button" value="click" OnClick="kk()"/&gt;
&lt;/body&gt;
</code></pre>

<p>When I put <code>lol = document.getElementById('lolz').value;</code> outside of the function <code>kk()</code>, like shown above, it doesn't work, but when I put it inside, it works. Can anyone tell me why?</p>


How to get an input text value in JavaScript

如何在JavaScript中获取输入文本值？<script language="javascript" type="text/javascript">    lol = document.getElementById('lolz').value;    function kk(){    alert(lol);    ...

问如何在JavaScript中获取输入文本值
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何在JavaScript中获取输入文本值EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何在JavaScript中获取输入文本值
EN