此正则表达式将每个小写单词转换为大写。我有一个全名输入字段。我确实希望用户看到他/她按下的每个单词的第一个字母在输入字段中都转换为大写。
我不知道如何正确替换当前输入字段中的选定字符。
$('input').on('keypress', function(event) {
var $this = $(this),
val = $this.val(),
regex = /\b[a-z]/g;
val = val.toLowerCase().replace(regex, function(letter) {
return letter.toUpperCase();
});
// I want this value to be in the input field.
console.log(val);
});
给定即：const str = "hello world"成为Hello world
const firstUpper = str.substr(0, 1).toUpperCase() + str.substr(1);
或者：
const firstUpper = str.charAt(0).toUpperCase() + str.substr(1);
或者：
const firstUpper = str[0] + str.substr(1);
您可以通过检查插入符号位置并重置插入符号位置，将第一个字母转换为大写字母，并且仍然避免光标跳到行首的烦人问题。我通过定义几个函数在表单上执行此操作，一个用于所有大写字母，一个用于正确大小写，一个用于仅初始大写字母...然后两个用于插入符号位置的函数，一个用于获取，一个用于设置：
function ProperCase(el) {
pos = getInputSelection(el);
s = $(el).val();
s = s.toLowerCase().replace(/^(.)|\s(.)|'(.)/g,
function($1) { return $1.toUpperCase(); });
$(el).val(s);
setCaretPosition(el,pos.start);
}
function UpperCase(el) {
pos = getInputSelection(el);
s = $(el).val();
s = s.toUpperCase();
$(el).val(s);
setCaretPosition(el,pos.start);
}
function initialCap(el) {
pos = getInputSelection(el);
s = $(el).val();
s = s.substr(0, 1).toUpperCase() + s.substr(1);
$(el).val(s);
setCaretPosition(el,pos.start);
}
/* GETS CARET POSITION */
function getInputSelection(el) {
var start = 0, end = 0, normalizedValue, range,
textInputRange, len, endRange;
if (typeof el.selectionStart == 'number' && typeof el.selectionEnd == 'number') {
start = el.selectionStart;
end = el.selectionEnd;
} else {
range = document.selection.createRange();
if (range && range.parentElement() == el) {
len = el.value.length;
normalizedValue = el.value.replace(/\r\n/g, "\n");
// Create a working TextRange that lives only in the input
textInputRange = el.createTextRange();
textInputRange.moveToBookmark(range.getBookmark());
// Check if the start and end of the selection are at the very end
// of the input, since moveStart/moveEnd doesn't return what we want
// in those cases
endRange = el.createTextRange();
endRange.collapse(false);
if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
start = end = len;
} else {
start = -textInputRange.moveStart("character", -len);
start += normalizedValue.slice(0, start).split("\n").length - 1;
if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
end = len;
} else {
end = -textInputRange.moveEnd("character", -len);
end += normalizedValue.slice(0, end).split("\n").length - 1;
}
}
}
}
return {
start: start,
end: end
};
}
/* SETS CARET POSITION */
function setCaretPosition(el, caretPos) {
el.value = el.value;
// ^ this is used to not only get "focus", but
// to make sure we don't have it everything -selected-
// (it causes an issue in chrome, and having it doesn't hurt any other browser)
if (el !== null) {
if (el.createTextRange) {
var range = el.createTextRange();
range.move('character', caretPos);
range.select();
return true;
}
else {
// (el.selectionStart === 0 added for Firefox bug)
if (el.selectionStart || el.selectionStart === 0) {
el.focus();
el.setSelectionRange(caretPos, caretPos);
return true;
}
else { // fail city, fortunately this never happens (as far as I've tested) :)
el.focus();
return false;
}
}
}
}
然后在准备好文档时，我将 keyup 事件侦听器应用于要检查的字段，但我只侦听可以实际修改字段内容的键（例如，我跳过“Shift”键......），如果用户点击“Esc”我恢复了字段的原始值...
$('.updatablefield', $('#myform')).keyup(function(e) {
myfield=this.id;
myfieldname=this.name;
el = document.getElementById(myfield);
// or the jquery way:
// el = $(this)[0];
if (e.keyCode == 27) { // if esc character is pressed
$('#'+myfield).val(original_field_values[myfield]); // I stored the original value of the fields in an array...
// if you only need to do the initial letter uppercase, you can apply it here directly like this:
initialCap(el);
} // end if (e.keyCode == 27)
// if any other character is pressed that will modify the field (letters, numbers, symbols, space, backspace, del...)
else if (e.keyCode == 8||e.keycode == 32||e.keyCode > 45 && e.keyCode < 91||e.keyCode > 95 && e.keyCode < 112||e.keyCode > 185 && e.keyCode < 223||e.keyCode == 226) {
// if you only need to do the initial letter uppercase, you can apply it here directly like this:
initialCap(el);
} // end else = if any other character is pressed //
}); // end $(document).keyup(function(e)
你可以在这里看到这个例子的工作小提琴：http: //jsfiddle.net/ZSDXA/
简单的说：
$this.val(val);
$(document).ready(function() {
$('input').on('keypress', function(event) {
var $this = $(this),
val = $this.val();
val = val.toLowerCase().replace(/\b[a-z]/g, function(letter) {
return letter.toUpperCase();
});
console.log(val);
$this.val(val);
});
});
正如@roXon所示，这可以简化：
$(document).ready(function() {
//alert('ready');
$('input').on('keypress', function(event) {
var $this = $(this),
val = $this.val();
val = val.substr(0, 1).toUpperCase() + val.substr(1).toLowerCase();
$this.val(val);
});
});
在我看来，另一种更好的解决方案是仅将元素样式设置为大写，然后执行逻辑服务器端。
这消除了任何 javascript 的开销，并确保在服务器端处理逻辑（无论如何都应该如此！）
$('input').on('keyup', function(event) {
$(this).val(function(i, v){
return v.replace(/[a-zA-Z]/, function(c){
return c.toUpperCase();
})
})
});
这将适用于 keyup 上的每个文本字段调用函数
其中 id 是您的文本字段的 ID，而 value 是您在文本字段中键入的值
function capitalizeFirstLetter(value,id)
{
if(value.length>0){
var str= value.replace(value.substr(0,1),value.substr(0,1).toUpperCase());
document.getElementById(id).value=str;
}
}
只使用这个这个工作在大写字符中的名字
style="text-transform:capitalize;
像
<asp:TextBox ID="txtName" style="text-transform:capitalize;" runat="server" placeholder="Your Name" required=""></asp:TextBox>
$('.form-capitalize').keyup(function(event) {
var $this = $(this),
val = $this.val(),
regex = /\b[a-z]/g;
val = val.toLowerCase().replace(regex, function(letter) {
return letter.toUpperCase();
});
this.value = val;
// I want this value to be in the input field.
console.log(val);
});